Isolation and cultivation of stem/progenitor cells from the amniotic membrane of umbilical cord and uses of cells differentiated therefrom

ABSTRACT

The present invention relates to a method of promoting skin rejuvenation in a subject. The method comprises administering to the subject an effective amount of a cellular extract of epithelial or mesenchymal stem/progenitor cells isolated from the amniotic membrane of the umbilical cord, wherein the cellular extract contains growth factors and peptides and is in the form of a supernatant into which the epithelial or mesenchymal stem/progenitor cells secrete the growth factors and peptides.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 15/859,375, filed Jul. 20, 2021, now U.S. Pat. No.11,066,645, which is a continuation of U.S. patent application Ser. No.14/715,342, filed May 18, 2015, now U.S. Pat. No. 10,066,209, which is adivisional of U.S. patent application Ser. No. 13/652,371 filed Oct. 15,2012, now U.S. Pat. No. 9,040,299, which is a divisional of U.S. patentapplication Ser. No. 12/091,018 filed Apr. 21, 2008, now U.S. Pat. No.8,287,854, which is the United States national stage patent applicationof International Application No. PCT/SG2006/000301, filed Oct. 11, 2006,which claims the benefit of priority of U.S. Provisional Application No.60/729,172, filed Oct. 21, 2005, the contents of each of which beinghereby incorporated by reference it its entirety for all purposes.

FIELD OF THE INVENTION

The present invention relates to a skin equivalent and a method forproducing the same, wherein the skin equivalent comprises a scaffold andstem/progenitor cells isolated from the amniotic membrane of umbilicalcord. These stem/progenitor cells may be mesenchymal (UCMC) and/orepithelial (UCEC) stem cells, which may then be further differentiatedto fibroblast and keratinocytes. Further described is a method forisolating stem/progenitor cells from the amniotic membrane of umbilicalcord, wherein the method comprises separating the amniotic membrane fromthe other components of the umbilical cord in vitro, culturing theamniotic membrane tissue under conditions allowing cell proliferation,and isolating the stem/progenitor cells from the tissue cultures. Theinvention also refers to therapeutic uses of these skin equivalents.Another aspect of the invention relates to the generation of amucin-producing cell using stem/progenitor cells obtained from theamniotic membrane of umbilical cord and therapeutic uses of suchmucin-producing cells. In yet another aspect, the invention relates to amethod for generating an insulin-producing cell using stem/progenitorcells isolated from the amniotic membrane of umbilical cord andtherapeutic uses thereof. The invention further refers to a method oftreating a bone or cartilage disorder using UCMC. Furthermore, theinvention refers to a method of generating a dopamin and tyrosinhydroxylase as well as a HLA-G and hepatocytes using UCMC and/or UCEC.The present invention also refers to a method of inducing proliferationof aged keratinocytes using UCMC.

BACKGROUND OF THE INVENTION

Stem cells are a cell population possessing the capacities to self-renewindefinitely and to differentiate in multiple cell or tissue types.Embryonic stem cells (from approximately days 3 to 5 afterfertilisation) proliferate indefinitely and can differentiatespontaneously into all tissue types: they are thus termed pluripotentstem cells (reviewed, for example, in Smith, A. G. (2001) Annu. Rev.Cell. Dev. Biol. 17, 435-462). Adult stem cells, however, are moretissue-specific and may have less replicative capacity: they are thustermed multipotent stem cells (reviewed, for example, in Paul, G. et al.(2002) Drug Discov. Today 7, 295-302). The “plasticity” of embryonic andadult stem cells relies on their ability to trans-differentiate intotissues different from their origin and, perhaps, across embryonic germlayers.

The ability of stem cells to self-renew is critical to their function asreservoir of primitive undifferentiated cells. In contrast, most somaticcells have a limited capacity for self-renewal due to telomereshortening (reviewed, for example, in Dice, J. F. (1993) Physiol. Rev.73, 149-159). Stem cell-based therapies thus have the potential to beuseful for the treatment of a multitude of human and animal diseases.

Stem cells as well as stem/progenitor cells can be derived fromdifferent sources. The “multi-lineage” potential of embryonic and adultstem cells has been extensively characterized. Even though the potentialof embryonic stem cells is enormous, their use implies many ethicalproblems. Therefore, non-embryonic stem cells derived from the bonemarrow stroma, fat tissue, dermis and umbilical cord blood have beenproposed as alternative sources. These cells can differentiate interalia into chondrocytes, adipocytes, osteoblasts, myoblasts,cardiomyocytes, astrocytes, and tenocytes in vitro and undergodifferentiation in vivo, making these stem cells—in general referred toas mesenchymal stem cells—promising candidates for mesodermal defectrepair and disease management.

In clinical use, however, harvesting of such mesenchymal stem cellscauses several problems. The collection of the cells is a mental andphysical burden to the patient as a surgical procedure is required toobtain the cells (for example, the collection of bone marrow is aninvasive technique performed with a biopsy needle that requires local oreven general anesthesia). Furthermore, in many cases the number of stemcells extracted is rather low. More importantly, no epithelial cells arederived or differentiated from these cells. This prompted the search forother possible sources of stem cells.

Umbilical cord blood has been identified as a rich source ofhaematopoietic stem/progenitor cells. However, the existence ofmesenchymal stem/progenitor cells is discussed controversially. On theone hand, such cells could not be isolated or successfully cultured fromterm umbilical cord blood (Mareschi, K. et al. (2001) Haematologica 86,1099-1100). At the same time, results obtained by Campagnoli, C. et al.(Blood (2001) 98, 2396-2402) as well as Erices, A. et al. (Br. J.Haematol. (2000) 109, 235-242) suggest that mesenchymal stem cells arepresent in several fetal organs and circulate in the blood of pre-termfetuses simultaneously with hematopoietic precursors. Accordingly,International Patent Application WO 03/070922 discloses isolation andculture-expansion methods of mesenchymal stem/progenitor cells fromumbilical cord blood and a differentiation method of such cells intovarious mesenchymal tissues. Isolation efficiencies of about 60% havebeen reported (Bieback, K. et al. (2004) Stem Cells 22, 625-634). In thesame study, both the time period from collection of the umbilical cordblood to isolation of the cells and the volume of the blood sample usedhave been determined as crucial parameters for achieving such a yield.However, it is still a matter of debate whether these stem/progenitorcells are indeed derived of umbilical cord tissue.

Recently, mesenchymal stem/progenitor cells have been successfullyisolated from umbilical cord tissue, namely from Wharton's jelly, thematrix of umbilical cord, (Mitchell, K. E. et al. (2003) Stem Cells 21,50-60; U.S. Pat. No. 5,919,702; US Patent Application 2004/0136967).These cells have been shown to have the capacity to differentiate, forexample, into a neuronal phenotype and into cartilage tissue,respectively. Furthermore, mesenchymal stem/progenitor cells have alsobeen isolated from the endothelium and the subendothelial layer of theumbilical cord vein, one of the three vessels (two arteries, one vein)found within the umbilical cord (Romanov, Y. A. et al. (2003) Stem Cells21, 105-110; Covas, D. T. et al. (2003) Braz. J. Med. Biol. Res. 36,1179-1183).

However, none of these approaches employed thus far has, for example,resulted in the isolation or cultivation of epithelial stem/progenitorcells as a source for epithelial cell-based therapies such as skinresurfacing, liver repair, bladder tissue engineering and otherengineered surface tissues. Skin resurfacing is an especially criticaland much needed medical treatment, which still needs a lot ofdevelopment as can be seen from the numbers available for example forthe USA. In the USA alone, there are 100.000 hospital treated burns peryear and 600.000 cases of surgical skin excision. The age relatedproblem of non-healing dermal wounds is far larger, with 11 to 12million patients being treated in the USA. For these pathologies Europeshows approximately the same numbers of patients.

The skin has three layers, the epidermis, the dermis and the fat layer,which all perform specific tasks. The epidermis is generated principallyby keratinocytes of epithelial origin, whereas the dermis is populatedby fibroblastic cells of mesenchymal origin. The epidermis is the thin,tough, top layer of skin. The outer portion of the epidermis, thestratum corneum, is water-proof and, when undamaged, prevents mostbacteria, viruses, and other foreign substances from entering the body.The epidermis also protects the internal organs, muscles, nerves, andblood vessels against trauma. The epidermis also contains islet-cells,which are part of the skin's immune system. The dermis, the next layerof skin, is a thick layer of fibrous and elastic tissue (made mostly ofthe polymers collagen and fibrillin) that gives the skin its flexibilityand strength. The dermis contains nerve endings, glands, hair folliclesand blood vessels.

The damage of the epidermis or dermis or of both layers (full thicknesswounds) by mechanical force, such as abrasion, surgical woundsassociated with the excision of skin cancers, or a loss of skin due toburns or other wounds, such as chronic venous ulcers, requires often thesubstitution of the skin. Depending on the extent of the damage thesubstitution with patient's own skin (autografts) taken fromnon-affected parts of the body is sometimes insufficient due to theextensive loss of skin. Therefore, a need exists to develop substitutesfor damaged skin either with help of autologous or allogeneic cells.

U.S. Pat. No. 6,479,875, for example, describes a skin substitute, whichconsists of a scaffold which incorporates dermis-forming cellsconsisting of mesenchymal stem cells. However, these mesenchymal stemcells, which are isolated from the bone marrow, are rare and typically10-20 cc aspirates have to be harvested from a patient in order toobtain enough mesenchymal stem cells.

Thus, there is still a need for methods and reliable sources useful forthe isolation and cultivation of epithelial stem/progenitor cells, whichcan be used for the further development of adequate skin substitutes.Furthermore, rapid and efficient methods which are ethically acceptableand do not pose a biomedical burden on the patient for the isolation ofepithelial and mesenchymal stem/progenitor cells are still required inorder to provide such cells in a sufficient amount for variousapplications in regenerative medicine and tissue engineering.

SUMMARY OF THE INVENTION

The invention provides a skin equivalent comprising a scaffold whichincludes cells derived from stem/progenitor cells isolated from theamniotic membrane of umbilical cord.

In one embodiment of the present invention the cells derived fromstem/progenitor cells are mesenchymal stem cells (UCMC: means in otherwords umbilical cord lining (amniotic membrane) mesenchymal stem cells;also referred to as CLMC) or epithelial stem cells (UCEC: means in otherwords umbilical cord lining (amniotic membrane) epithelial stem cells;also referred to as CLEC).

The cells used for the skin equivalent of the present invention can beautologous, xenogeneic or allogeneic cells.

Furthermore the cells used for the skin equivalent of the presentinvention can be of mammalian origin. In one embodiment of the presentinvention the cells are of human origin.

In another embodiment the scaffold of the skin equivalent can furtherinclude additional cell lines, for example, but not limited to, vesselendothelial cells or dermal microvascular endothelial cells. In oneembodiment these vessel endothelial cells are derived from the umbilicalcord. Depending on the donor the endothelial cells can be of mammalianor human origin.

In one embodiment of the invention the skin equivalent comprises ascaffold, which comprises a biodegradable material. In yet anotherembodiment this scaffold includes or consist of, but is not limited, toa material such as agarose, polycaprolactone, niobium coated carbon,chitosan, collagen, hyaluronic acid, calcium phosphate, starch,hydroxyapatite, fibrin, alginate, poly-glycolic acid, carbon nanofibres, porous polycarbonate, polytetrafluoroethylene, polylactide andmixtures thereof. In one example of the present invention the scaffoldmaterial is polycarbonate.

The present invention further provides a scaffold which scaffold mayinclude at least one extracellular matrix as support for the cellsderived from stem/progenitor cells isolated from the amniotic membraneof umbilical cord. The extracellular matrix component may include, butis not limited to one or more of materials such as collagen, elastin,intercellular adhesion molecules, laminin, heparin, fibronectin,proteoglycans, tenascin, fibrillin and mixtures thereof. In one examplethe extracellular matrix component is collagen. In another embodimentthe extracellular matrix is provided by the stem/progenitor cell itselfby secretion of the respective extracellular matrix component, e.g.collagen.

In yet another embodiment of the present invention the UCMC and/or UCECcomprised in the skin equivalent of the present invention are able toproliferate and further differentiate in fibroblasts and keratinocytes,respectively.

The invention further provides a method for the production of a skinequivalent comprising:

-   -   providing a scaffold,    -   placing cells derived from stem/progenitor cells isolated from        the amniotic membrane of umbilical cord in or onto said        scaffold, and    -   incubating said scaffold in a first medium, which allows said        cells to proliferate and further differentiate.

In one embodiment said cells derived from stem/progenitor cells aremesenchymal stem cells (UCMC) or epithelial stem cells (UCEC).

In another embodiment of the present invention said first mediumcomprises a medium adapted for the cultivation of fibroblast orkeratinocytes when said scaffold comprises UCMC and UCEC, respectively.

The invention further provides a method of treating a skin disordercomprising contacting the skin equivalent of the present invention onsaid skin disorder. The invention further provides the use of a skinequivalent of the present invention or a skin equivalent obtained by themethod of the present invention for the manufacture of a pharmaceuticalcomposition as well as the pharmaceutical composition for the treatmentof burned skin and an ulcer, to name only a few illustrative examples ofskin disorders.

The invention further provides a cell bank comprising a skin equivalentof the present invention or a skin equivalent obtained by a method ofthe present invention.

The invention also provides a method for the generation of amucin-producing cell comprising:

-   -   placing umbilical cord amniotic lining membrane epithelial or        mesenchymal stem cells (UCEC and UCMC, respectively) in a        container, and    -   incubating said UCEC or UCMC in a medium adapted for the        cultivation of secretory cells. Such mucin-producing cells can        be used for treating cells of the ocular surface or the        respiratory tracts, which are affected, e.g., by smoke.

The Yet in still another embodiment the present invention provides amethod for generating an insulin-producing cell, comprising:

-   -   cultivating cells derived from stem/progenitor cells isolated        from the amniotic membrane of umbilical cord, and    -   proliferating and differentiating said cells in a suitable        cultivation medium into β-islet cells.

In yet other embodiments the invention provides insulin-producing cellsobtained by a method of the present invention, described above, andtreating a disorder associated with an imbalance in the insulin level,comprising administering to a mammal an insulin producing cell obtainedby the method of the present invention as described above.

In a further embodiment of the present invention a method of treating abone disorder comprising administering osteoblasts which are producedfrom mesenchymal stem cells isolated from the amniotic membrane of theumbilical cord (UCMC) to a patient is provided. Also provided is amethod of treating a cartilage disorder comprising administration ofchondrocytes, which are produced from mesenchymal stem cells isolatedfrom the amniotic membrane of the umbilical cord (UCMC) to a patient.

Still another embodiment of the present invention provides a method ofgenerating a dopamin and tyrosin hydroxylase producing cell, comprising:

-   -   cultivating cells derived from stem/progenitor cells isolated        from the amniotic membrane of umbilical cord, preferably UCMC,        and    -   proliferating and differentiating the cells in a suitable        cultivation medium into dopamin and tyrosin hydroxylase        producing cells.

In addition, the present invention refers to a method of producing humanleukocyte antigen G (HLA-G) or hepatic like cells using UCMC and UCEC,respectively.

In another embodiment of the present invention, it is referred to amethod of inducing proliferation of aged keratinocytes comprising:

-   -   culturing aged keratinocytes in a suitable growth medium, and        adding mesenchymal stem cells (UCMC) of the amniotic membrane of        the umbilical cord to the aged keratinocytes to induce        proliferation of the aged keratinocytes.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with reference to the detaileddescription when considered in conjunction with the non-limitingexamples and the drawings, in which:

FIG. 1A depicts epithelial cell outgrowth from umbilical cord amnioticmembrane by the method of direct tissue explant (40× magnification) atday 2 of tissue culture. FIGS. 1B and 1C depict epithelial celloutgrowth from umbilical cord amniotic membrane by the method of directtissue explant (40× magnification) at day 5 of tissue culture. Cellculture plastic surfaces were coated with collagen 1/collagen 4 mixtures(1:2; Becton Dickinson) before placing the amniotic membrane on thesurface. The amniotic membrane specimens were submerged in 5 ml EpiLifemedium or Medium 171 (both from Cascade Biologics). Medium was changedevery 2 or 3 days and cell outgrowth by explant was monitored underlight microscopy. Microphotographs were taken at different timeintervals as stated above. The observed polyhedral cell morphology istypical of epithelial cells.

FIGS. 2A and 2C depict enzymatic digestion of the umbilical cordsegments yielding similar epithelial (40× magnification) cells at day 2.FIGS. 2B and 2D depict enzymatic digestion of the umbilical cordsegments yielding similar epithelial (40× magnification) cells at day 5.Umbilical cord amniotic membrane was divided into small pieces of 0.5cm×0.5 cm and digested in 0.1% (w/v) collagenase type 1 solution (RocheDiagnostics) at 37° C. for 8 hours. The samples were vortexed every 30min for 3 min. Cells were harvested by centrifugation at 4000 rpm for 30min. Cell pellets were resuspended in EpiLife medium or Medium 171 (bothfrom Cascade Biologics) supplemented with 50 μg/ml insulin-like growthfactor-1 (IGF-1), 50 μg/ml platelet-derived growth factor-BB (PDGF-BB),5 μg/ml transforming growth factor-β1 (TGF-β1) and 5 μg/ml insulin (allobtained from R&D Systems), counted and seeded on 10 cm tissue culturedishes pre-coated with collagen 1/collagen 4 mixtures (1:2; BectonDickinson) at density of 1×10⁶ cells/dish. After 24 hours, attachedcells were washed with warm phosphate buffered saline (PBS) and theculture medium was replaced with EpiLife medium or Medium 171 (both fromCascade Biologics). The medium was changed every 2 or 3 days, and celloutgrowth was monitored under light microscopy. Microphotographs weretaken at different time intervals as stated above. Once again the cellsdemonstrated typical epithelial cell polyhedral morphology.

FIGS. 3A, 3B, 3C, and 3D depict outgrowing mesenchymal cells explantedfrom umbilical cord amniotic membrane. Cellular outgrowth was observedas early as 48 hours after placement in tissue culture dishes using DMEMsupplemented with 10% fetal calf serum (FCS) as culture medium (40×magnification). The explants were submerged in 5 ml DMEM (Invitrogen)supplemented with 10% fetal bovine serum (Hyclone) (DMEM/10% FBS).Medium was changed every 2 or 3 days. Cell outgrowth was monitored underlight microscopy. Microphotographs were taken at different timeintervals. The cells were characterized by their spindle shapedmorphology, and migrated and expanded both easily and quickly in vitro,closely resembling fibroblasts.

FIG. 4A (40× magnification) depicts mesenchymal cells from umbilicalcord amniotic membrane cells isolated by collagenase enzymaticdigestion, showing mesenchymal cells isolated from umbilical cordamniotic membrane at day 2. FIG. 4B (40× magnification) depictsmesenchymal cells from umbilical cord amniotic membrane cells isolatedby collagenase enzymatic digestion, showing cell proliferation observedat day 5. Umbilical cord amniotic membrane was divided into small piecesof 0.5 cm×0.5 cm and digested in 0.1% (w/v) collagenase type1 solution(Roche Diagnostics) at 37° C. for 6 hours. The samples were vortexedevery 15 min for 2 min. Cells were harvested by centrifugation at 4000rpm for 30 min. Cell pellets were resuspended in DMEM/10% FBS, countedand seeded on 10 cm tissue culture dish at density of 1×10⁶ cells/dish.Medium was changed every 2 or 3 days. Cell outgrowing was monitoredunder light microscopy. Microphotographs were taken at different timeintervals. Once again, cells demonstrated spindle shaped morphologytypical of mesenchymal cells as fibroblasts.

FIG. 5A (40× magnification) depicts the morphology in serum culturecondition (DMEM/10% FCS) of normal dermal fibroblasts (NF109 cells).FIG. 5B (40× magnification) depicts the morphology in serum-free culturecondition (DMEM) of normal dermal fibroblasts (NF109 cells). FIG. 5C(40× magnification) depicts the morphology in serum culture condition(DMEM/10% FCS) of adipose-derived mesenchymal cells (ADMC). FIG. 5D (40×magnification) depicts the morphology in serum-free culture condition(DMEM) of adipose-derived mesenchymal cells (ADMC). FIGS. 5E and 5G (40×magnification) depict the morphology in serum culture condition(DMEM/10% FCS) of umbilical cord amniotic membrane mesenchymal cells(UCMC) isolated according to the method of the invention. FIGS. 5F and5H (40× magnification) depict the morphology in serum-free culturecondition (DMEM) of umbilical cord amniotic membrane mesenchymal cells(UCMC) isolated according to the method of the invention. Morphology ofNF and ADMC cultured in serum starvation conditions (DMEM only) isreflected by flatter cells and less dense cytoplasm as compared withserum rich conditions (DMEM/10% FCS) where cells are more rounded with adense cytoplasm. No change in morphology was observed in both UCMCgroups cultured under identical conditions of serum-free vs. serum richmedia, indicating a difference in behavior and physiology of theselatter mesenchymal cells.

FIG. 6 (40× magnification) depicts UCMC isolated according to theinvention cultured in DMEM/10% FCS at days 3 and 7 without a 3T3 feederlayer. The cells are seen to be growing well, and are forming a colony(vertical growth) instead of exhibiting radial spread. Once again, thisindicates a difference in behavior of these mesenchymal cells ascompared to their more differentiated counterparts.

FIG. 7 (40× magnification) depicts colony formation of umbilical cordepithelial cells (UCEC) cultured on a 3T3 feeder layer at days 3 and 7.This appearance is similar to that of normal skin derived epithelialkeratinocyte stem cells. In the latter, the 3T3 feeder layer maintainsstemness of the cells.

FIG. 8A (40× magnification) depicts obvious colony formation ofumbilical cord mesenchymal cells (UCMC) isolated according to theinvention cultured on a 3T3 feeder layer at days 3 and 7. The 3T3 feederlayer normally suppresses the growth of differentiated mesenchymal cellsas human dermal fibroblasts. Once again, this indicates a difference inbehavior of these mesenchymal cells as compared to their moredifferentiated counterparts. FIG. 8B shows the colony forming efficiencyassay of the umbilical cord mesenchymal cells.

FIG. 9-1 shows Western blot analysis by which the expression of OCT-4 inUCEC and UCMC isolated according to the invention, was compared to theexpression of these markers in human dermal fibroblasts (NF), in bonemarrow mesenchymal cells (BMSC) and adipose-derived mesenchymal cells(ADMC). FIG. 9-2 shows Western blot analysis by which the expression ofSTAT3 in UCEC and UCMC isolated according to the invention, was comparedto the expression of these markers in human dermal fibroblasts (NF), inbone marrow mesenchymal cells (BMSC) and adipose-derived mesenchymalcells (ADMC). FIG. 9-3 shows Western blot analysis by which theexpression of STAT3 in UCEC and UCMC isolated according to theinvention, was compared to the expression of these markers in humandermal fibroblasts (NF), in bone marrow mesenchymal cells (BMSC) andadipose-derived mesenchymal cells (ADMC). FIG. 9-4 shows Western blotanalysis by which the expression of PLGF in UCEC and UCMC isolatedaccording to the invention, was compared to the expression of thesemarkers in human dermal fibroblasts (NF), in bone marrow mesenchymalcells (BMSC) and adipose-derived mesenchymal cells (ADMC). FIG. 9-5shows Western blot analysis by which the expression of PLGF in UCEC andUCMC isolated according to the invention, was compared to the expressionof these markers in human dermal fibroblasts (NF), in bone marrowmesenchymal cells (BMSC) and adipose-derived mesenchymal cells (ADMC).FIG. 9-6 shows Western blot analysis by which the expression of CTGF inUCEC and UCMC isolated according to the invention, was compared to theexpression of these markers in human dermal fibroblasts (NF), in bonemarrow mesenchymal cells (BMSC) and adipose-derived mesenchymal cells(ADMC). FIG. 9-7 shows Western blot analysis by which the expression ofCTGF in UCEC and UCMC isolated according to the invention, was comparedto the expression of these markers in human dermal fibroblasts (NF), inbone marrow mesenchymal cells (BMSC) and adipose-derived mesenchymalcells (ADMC). FIG. 9-8 shows Western blot analysis by which theexpression of PDGF in UCEC and UCMC isolated according to the invention,was compared to the expression of these markers in human dermalfibroblasts (NF), in bone marrow mesenchymal cells (BMSC) andadipose-derived mesenchymal cells (ADMC). FIG. 9-9 shows Western blotanalysis by which the expression of PDGF in UCEC and UCMC isolatedaccording to the invention, was compared to the expression of thesemarkers in human dermal fibroblasts (NF), in bone marrow mesenchymalcells (BMSC) and adipose-derived mesenchymal cells (ADMC). FIG. 9-10shows Western blot analysis by which the expression of VEGF in UCEC andUCMC isolated according to the invention, was compared to the expressionof these markers in human dermal fibroblasts (NF), in bone marrowmesenchymal cells (BMSC) and adipose-derived mesenchymal cells (ADMC).FIG. 9-11 shows Western blot analysis by which the expression of VEGF inUCEC and UCMC isolated according to the invention, was compared to theexpression of these markers in human dermal fibroblasts (NF), in bonemarrow mesenchymal cells (BMSC) and adipose-derived mesenchymal cells(ADMC). FIG. 9-12 shows Western blot analysis by which the expression ofFGF-2 in UCEC and UCMC isolated according to the invention, was comparedto the expression of these markers in human dermal fibroblasts (NF), inbone marrow mesenchymal cells (BMSC) and adipose-derived mesenchymalcells (ADMC). FIG. 9-13 shows Western blot analysis by which theexpression of FGF-2 in UCEC and UCMC isolated according to theinvention, was compared to the expression of these markers in humandermal fibroblasts (NF), in bone marrow mesenchymal cells (BMSC) andadipose-derived mesenchymal cells (ADMC). FIG. 9-14 shows Western blotanalysis by which the expression of HDGF in UCEC and UCMC isolatedaccording to the invention, was compared to the expression of thesemarkers in human dermal fibroblasts (NF), in bone marrow mesenchymalcells (BMSC) and adipose-derived mesenchymal cells (ADMC). FIG. 9-15shows Western blot analysis by which the expression of HDGF in UCEC andUCMC isolated according to the invention, was compared to the expressionof these markers in human dermal fibroblasts (NF), in bone marrowmesenchymal cells (BMSC) and adipose-derived mesenchymal cells (ADMC).FIG. 9-16 shows Western blot analysis by which the expression of SCF inUCEC and UCMC isolated according to the invention, was compared to theexpression of these markers in human dermal fibroblasts (NF), in bonemarrow mesenchymal cells (BMSC) and adipose-derived mesenchymal cells(ADMC). FIG. 9-17 shows Western blot analysis by which the expression ofα-SMA in UCEC and UCMC isolated according to the invention, was comparedto the expression of these markers in human dermal fibroblasts (NF), inbone marrow mesenchymal cells (BMSC) and adipose-derived mesenchymalcells (ADMC). FIG. 9-18 shows Western blot analysis by which theexpression of fibronectin in UCEC and UCMC isolated according to theinvention, was compared to the expression of these markers in humandermal fibroblasts (NF), in bone marrow mesenchymal cells (BMSC) andadipose-derived mesenchymal cells (ADMC). FIG. 9-19 shows Western blotanalysis by which the expression of fibronectin in UCEC and UCMCisolated according to the invention, was compared to the expression ofthese markers in human dermal fibroblasts (NF), in bone marrowmesenchymal cells (BMSC) and adipose-derived mesenchymal cells (ADMC).FIG. 9-20 shows Western blot analysis by which the expression of decorinin UCEC and UCMC isolated according to the invention, was compared tothe expression of these markers in human dermal fibroblasts (NF), inbone marrow mesenchymal cells (BMSC) and adipose-derived mesenchymalcells (ADMC). FIG. 9-21 shows Western blot analysis by which theexpression of syndecan-1 in UCEC and UCMC isolated according to theinvention, was compared to the expression of these markers in humandermal fibroblasts (NF), in bone marrow mesenchymal cells (BMSC) andadipose-derived mesenchymal cells (ADMC). FIG. 9-22 shows Western blotanalysis by which the expression of syndecan-2 in UCEC and UCMC isolatedaccording to the invention, was compared to the expression of thesemarkers in human dermal fibroblasts (NF), in bone marrow mesenchymalcells (BMSC) and adipose-derived mesenchymal cells (ADMC). FIG. 9-23shows Western blot analysis by which the expression of syndecan-2 inUCEC and UCMC isolated according to the invention, was compared to theexpression of these markers in human dermal fibroblasts (NF), in bonemarrow mesenchymal cells (BMSC) and adipose-derived mesenchymal cells(ADMC). FIG. 9-24 shows Western blot analysis by which the expression ofsyndecan-3 in UCEC and UCMC isolated according to the invention, wascompared to the expression of these markers in human dermal fibroblasts(NF), in bone marrow mesenchymal cells (BMSC) and adipose-derivedmesenchymal cells (ADMC). FIG. 9-25 shows Western blot analysis by whichthe expression of syndecan-3 in UCEC and UCMC isolated according to theinvention, was compared to the expression of these markers in humandermal fibroblasts (NF), in bone marrow mesenchymal cells (BMSC) andadipose-derived mesenchymal cells (ADMC). FIG. 9-26 shows Western blotanalysis by which the expression of syndecan-4 in UCEC and UCMC isolatedaccording to the invention, was compared to the expression of thesemarkers in human dermal fibroblasts (NF), in bone marrow mesenchymalcells (BMSC) and adipose-derived mesenchymal cells (ADMC). FIG. 9-27shows Western blot analysis by which the expression of Bmi-1 in UCEC andUCMC isolated according to the invention, was compared to the expressionof these markers in human dermal fibroblasts (NF), in bone marrowmesenchymal cells (BMSC) and adipose-derived mesenchymal cells (ADMC).FIG. 9-28 shows Western blot analysis by which the expression of LIF inUCEC and UCMC isolated according to the invention, was compared to theexpression of these markers in human dermal fibroblasts (NF), in bonemarrow mesenchymal cells (BMSC) and adipose-derived mesenchymal cells(ADMC). FIG. 9-29 shows secretion of Leukemia inhibitory factor detectedby Western blot analysis in supernatants of umbilical cord mesenchymaland epithelial stem cell culture in comparison with bone marrow, adiposederived stem cells, human dermal fibroblasts and epidermalkeratinocytes. FIG. 9-30 shows secretion of highly secreted ActivinA andFollistatin detected by ELISA assay in supernatants of umbilical cordmesenchymal and epithelial stem cell culture in comparison with bonemarrow, adipose derived stem cells, human dermal fibroblasts andepidermal keratinocytes. FIG. 9.1a and FIG. 9.1b describe the result ofan experiment in which UCMC were cultured in PTT-4 medium. The coloniesin the culture dishes (FIG. 9.1a ) were fixed and stained with an antiOct-4 antibody (FIG. 9.1b ) to confirm expression of the transcriptionfactor (FIG. 9.1.b)

FIG. 10-1 shows indirect immunofluorescent analysis of markers ofepithelial cells expressed in umbilical cord epithelial stem cells:cytokeratins (CK)-general, CK17, CK6, CK10, CK19, CK18, CK16, CK15. FIG.10-2 shows indirect immunofluorescent analysis of markers of epithelialcells expressed in umbilical cord epithelial stem cells: Hemidesmosomecomponents-integrin alpha6, integrin beta4; Desmosome components. FIG.10-3 shows indirect immunofluorescent analysis of markers of epithelialcells expressed in umbilical cord epithelial stem cells: Basementmembrane components—laminin1, laminin5, collagen IV, collagen VII. FIG.10-4 shows indirect immunofluorescent analysis of markers of epithelialcells expressed in umbilical cord epithelial stem cells: extracellularmatrix components integrin-beta1 and fibronectin.

FIGS. 11-1 to FIG. 11-4 show cytokine array analysis of secretedcytokines and growth factors by umbilical cord mesenchymal stem cells(UCMC) in comparison with human bone-marrow mesenchymal stem cells. Inmore detail, FIG. 11-1 shows an expression profile of secreted cytokinesand growth factors by umbilical cord mesenchymal cells, FIG. 11-2 alsoshows an expression profile of secreted cytokines and growth factors byumbilical cord mesenchymal cells, FIG. 11-3 further shows an expressionprofile of secreted cytokines and growth factors by umbilical cordmesenchymal cells, and also FIG. 11-4 shows an expression profile ofsecreted cytokines and growth factors by umbilical cord mesenchymalcells.

FIGS. 12-1 to FIG. 12-7 show cytokine array analysis of secretedcytokines and growth factors by umbilical cord epithelial stem cells(UCEC) in comparison with human epidermal keratinocytes. In more detail,FIG. 12-1 shows an expression profile of secreted cytokines and growthfactors by umbilical cord epithelial cells, FIG. 12-2 also shows anexpression profile of secreted cytokines and growth factors by umbilicalcord epithelial cells, FIG. 12-3 shows an expression profile of secretedcytokines and growth factors by human epidermal keratinocytes, FIG. 12-4also shows an expression profile of secreted cytokines and growthfactors by human epidermal keratinocytes, FIG. 12-5 shows an expressionprofile of secreted cytokines and growth factors by umbilical cordepithelial cells, FIG. 12-6 shows a spotting of a chip used for cytokinearray, and FIG. 12-7 also shows a spotting of a chip used for cytokinearray.

FIG. 13-1 shows UCMC cells cultured in DMEM supplemented with 10% fetalcalf serum (FCS)., FIG. 13-2 shows UCMC cells cultured in serum-freemedia PTT-1. FIGS. 13-3 and 13-4 show UCMC cells cultured in inserum-free media PTT-2. FIG. 13-5 shows UCMC cells cultured in inserum-free media PTT-3. FIG. 13-6 shows the growth of adipose derivedstromal cells in serum free medium PTT-3. FIG. 13-7 shows the growth ofbone marrow derived stromal cells in serum free medium PTT-3.

FIGS. 14-1 to 14-6 show global gene expression in umbilical cordepithelial and mesenchymal stem cells analyzed by DNA microarray. UCECexpressed a total of 28055 genes and UCMC expressed a total of 34407genes. There are 27308 overlapping genes expressing in both cell types.747 genes expressed were unique to UCEC and 7099 genes expressed wereunique to UCMC. The selected genes of interest are presented in thisFigure. Both stem cell types expressed 140 genes related to embryonicstem cells and embryonic development.

FIG. 15 shows a schematic illustration of expansion of umbilical cordepithelial and mesenchymal stem cells using repetitive explants ofumbilical cord lining membrane tissues.

FIG. 16 depicts a cross section of an umbilical cord demonstrating theumbilical cord amniotic lining membrane (LM), the contained Wharton'sjelly (WJ), as well as two umbilical arteries (UA) and one umbilicalvein (UV) supported within this jelly.

FIG. 17A depicts direct (in-vitro) differentiation of epithelial cellsisolated from the amniotic membrane of umbilical cord (UCEC) into skinepidermal keratinocytes. FIGS. 17B and 17C depict direct in-vitrodifferentiation of mesenchymal cells isolated from the amniotic membraneof umbilical cord (UCMC) into osteoblasts and adipocytes.

FIGS. 18a and 18b depicts the in vitro differentiation of epithelialcells isolated from the amniotic lining membrane of umbilical cord(UCEC) into skin epidermal keratinocytes (FIG. 18a ; pictures takenafter 7 days of cell culturing), and in-vitro differentiation ofmesenchymal cells isolated from the amniotic lining membrane ofumbilical cord (UCMC) into fibroblasts (FIG. 18b ; photographs takenafter 7 days of cell culturing).

FIG. 19 (200× magnification) depicts a fully developed skin equivalentobtained by the method of the present invention. The epithelial layer isformed by the keratinocytes, which were produced by differentiation andincubation of UCEC in a medium as specified in the method of the presentinvention. The dermal layer, which is formed by the keratinocytesproduced by differentiation and incubation of UCMC in a medium asspecified in the method of the present invention, also grows in theextracellular collagen matrix and included in the skin equivalent of thepresent invention.

FIG. 20a (1200× magnification) depicts the keratinocyte surfaceappearance of a skin equivalent (CSE-1) produced according to the methoddescribed in Example 12—FIG. 20b (2000× magnification) depicts theappearance of UCMC derived fibroblasts in collagen scaffold (lattices),which were obtained according to the method described in Example 12.

FIG. 21a (2000× magnification) depicts the keratinocyte surfaceappearance of a skin equivalent (CSE-2) produced according to the methoddescribed in Example 13. FIG. 21b (3000× magnification) depicts theappearance of UCMC derived fibroblasts in collagen lattices, which wereobtained according to the method described in Example 13.

FIG. 22a shows the development of mucin-producing cells after 3, 7 and10 days of culturing in PTT-6. FIG. 22b shows the mucin produced by UCEC(referred to as pellets 1, 2, 3, 6 (P1, P2 etc.) of UCEC-17) cultured inPTT-6 detected by their molecular weight in a SDS-PAGE. For furtherdetails see Example 16.

FIGS. 23a and 23b depicts UCEC which were incubated in PTT-10 togetherwith nicotinamide. As can be seen from the photographs UCEC which wereincubated with nicotinamide differentiated into β-islet cells (FIG. 23b), whereas UCEC grown in PTT-10 only did not (FIG. 23a ).

FIG. 24A depicts negative staining observed with undifferentiated UCMCcells. FIG. 24B depicts the chondrogenic differentiation of UCMC intochondrocytes for the development of cartilage. Chondrocytes developedfrom UCMC upon induction with modified PTT-5 (see Example 17) have beenstained with Alcian Blue. Positive staining of chondrocytes was observedin.

FIG. 25 shows insulin expression in multiple samples of UCEC underinduction of ES Cult medium (Stem Cell Technologies Inc., Vancouver,Canada) or BBRC06 medium as described in Example 15. This experimentshows that UCEC have the potential to differentiate intoinsulin-producing cells which can be used for the treatment of diabetes.

FIG. 26A and FIG. 26B demonstrate the secretion and expression oftyrosine hydroxylase (TH) and dopamine by differentiated UCMC cells asdescribed in more detail in Example 18. Dopamine is used for thetreatment of patient with Parkinson Syndrome. FIG. 26C shows a negativecontrol.

FIG. 27A and FIG. 27B demonstrate secretion and expression of HLA-G bydifferentiated UCMC and UCEC cells as described in Example 19.

FIGS. 28A, 28B and 28C show the results of the experiment in which theproliferation of aged skin keratinocytes (asK) and human dermalfibroblasts have been induced by UCMC. Skin cells used derived from of50 or 60 year old patients have been used for this experiment. Thisexperiment demonstrates the proliferative effects of UCMC which cantherefore also be used for wound healing, tissue repair, regeneration,rejenuvation, cosmetic and skin care applications.

FIG. 29A shows organotypic coculture of UCMC and UCEC in collagenelattices. Epithelia were observed on these mesenchymal tissueequivalents (MTE) constructs. FIG. 29B shows skin-resemble structures ofcultured skin equivalents. UCMC cell-populated collagen lattices supportfull differentiation of human keratinocyte stem cells. These figuresshow that UCMC and UCEC can be used to construct organ-like tissuein-vitro for tissue repair and regeneration and drug discovery.

FIG. 30A and FIG. 30B demonstrate that UCMC cells are able to grow intoand onto collagen and bone scaffolds of TissueFleece® E (Baxter AG,Austria) and BoneSave® (Stryker Inc., MI, USA). The figures show livingUCMC which have been stained and which were grown on the scaffolds asdescribed in Example 2.

FIG. 31A shows the UCMC populated scaffolds in growth medium before theimplantation. FIG. 31B and FIG. 31C refer to an experiment as describedin Example 22 demonstrating the angiogenic properties of UCMC populatedcollagen scaffolds which were implanted in mice. After 21 days,macroscopic as well as microscopic vascularization was observed.

FIGS. 32A to 32C demonstrate the clinical application of UCMC fortreatment of full thickness burns wounds (3^(rd) degree). FIG. 32A showswound bed preparation on full thickness burns of 53 years old femalepatient. UCMC cells were inoculated onto Biobrane wound dressings (DowHickam Pharmaceuticals, Texas, USA). UCMC-Biobrane constructs weretransferred onto wounds (FIG. 32B) as described in Example 23. Completehealing was seen at day 7 without skin graft and stable up to 3 monthfollow-up (FIG. 32C).

FIG. 33 demonstrates the clinical application of UCMC for the treatmentof partial-thickness wounds (2^(nd) degree) of 2 years old, male patientas described in example 24. Complete healing of the wound was observedat day 3.

FIG. 34 demonstrates the clinical application of UCMC for the treatmentof full thickness burns wounds (3^(rd) degree) of a 2 year old malepatient. UCMC were mixed with SoloSite® gel (Smith & Nephew, Hull, UK)and pasted onto wound as described in example 23. Complete healing ofthe wound with this method was observed at day 5.

FIG. 35 demonstrates the clinical application of UCMC for the treatmentof a non-healing radiation wound in a 1 year old child, who hadhemangioma. The original wound did not heal over a period of 90 dayswith conventional wound treatment. UCMC were cultured onto Tegaderm®wound dressing and transferred onto wounds as described in example 25.The radiation wound was healed completely over a period of 20 days ofUCMC cell therapy.

FIG. 36 and FIG. 37A and FIG. 37B demonstrate the clinical applicationof UCMC for treatment of a non-healing diabetic wound (FIG. 36), anon-healing diabetic food wound (FIG. 37B) and a failed skin flap donorsite wound (FIG. 37A). The latter two were failed to heal underconventional treatment over a period of 6 years. UCMC were cultured andmixed with SoloSite® gel (Smith & Nephew, Hull, UK) as described inExample 26.

FIG. 38 shows albumin expression of UCEC under induction of BBRC06Hmedium (BBRC06H medium is modified version of BBRC06 as described inexample 15 without addition of nicotinamide and with addition ofOncostatin-M at 50 μg/ml). This experiment shows that UCEC havepotential to differentiate into hepatocytes, which can be used for thetreatment of liver diseases or in-vitro models for testing cytotoxicityof new drugs.

DETAILED DESCRIPTION

The invention is based on the surprising finding that skin equivalentscan be formed using the amniotic membrane of umbilical cord as a source,from which stem/progenitor cells such as mesenchymal and epithelialstem/progenitor cells can be successfully isolated and expanded under invitro conditions. Using these cells, the invention provides a skinequivalent comprising or consisting essentially of a scaffold includingcells derived from stem/progenitor cells derived from the amnioticmembrane of umbilical cord. Even more surprising is the finding thatthese stem/progenitor cells show embryonic stem cell-likecharacteristics. The amniotic membrane (also called amniotic liningmembrane), i.e. thin innermost membranous sac enclosing the placenta anddeveloping embryo of mammals, has recently been used as a naturalsubstrate in ocular surface reconstruction and as a biological substratefor expanding limbal epithelial stem cells (cf., e.g., Anderson, D. F.et al. (2001) Br. J. Ophthalmol. 85, 567-575; Grüterich, M. et al.(2003) Surv. Ophthalmol. 48, 631-646). However, no methods have beendescribed thus far for the isolation of stem/progenitor cells from theamniotic membrane, at least for humans, nor has the amniotic membranecovering the umbilical cord been reported as a source for stem cellswhich can be used to produce the skin equivalent of the presentinvention.

A scaffold is employed as basis for the skin equivalent of the presentinvention. Scaffolds have been used extensively in the area of tissueengineering either to construct a neo-tissue that can be implanted torepair a defect site in the body or as a cell container in bioartificialdevices. Scaffolds form a three dimensional matrix that serves as atemplate for cell proliferation and ultimately tissue formation.Culturing cells in a scaffold typically involves seeding cellsthroughout the scaffold and allowing the cells to proliferate in thescaffold for a pre-determined amount of time.

Thus, the present provides a skin equivalent and a method to obtain thesame wherein in one embodiment the scaffold includes or is made of abiodegradable material. To use a biodegradable material for the scaffoldis advantageous, e.g., for tissue engineering, wherein the scaffoldscontaining the cells are used to repair defect sites in living tissue,e.g. skin. One useful aspect of the scaffolds used in the presentinvention is their penetrability for the cell medium that is necessaryto transport nutrients and metabolites to and from the cells includedinto said scaffold. In the present invention, scaffolds further includeor are made from materials such as agarose, polycaprolactone (Endres, M.et al., Tissue Engineering, 2003, Vol. 9, No. 4, P. 689-702), niobiumcoated carbon, chitosan, hydroxyapatite-tricalcium phosphate (Harris, C.T. and Cooper, L. F., Comparison of matrices for hMSC delivery, 2004, P.747-755), collagen, hyaluronic acid, calcium phosphate, starch,hydroxyapatite, fibrin, alginate, poly-glycolic acid, carbon nanofibres, polytetrafluoroethylene, polylactic acid (Moran, J. et al.,Tissue Engineering, 2003, Vol. 9, No. 1, P. 63-70) and mixtures thereof.Foam scaffolds as those described in U.S. Pat. No. 6,231,879 which arebased on thermoplastic elastomers, such as polyamide, polyester,polyethylene polyvinylidene fluoride, polyethyurethane or silicone, canalso be used in the present invention. In one embodiment, porouspolycarbonate is used as scaffold material.

The scaffold in which the cell species are encapsulated may have anyregular or irregular (outer) shape. If the scaffolds are, e.g., used intissue engineering of the skin the shape of the scaffold will fit theshape of the defect site the scaffold will be used for. The scaffoldwhich are used in the present invention are normally about 1 μm to about5 μm thick and in some embodiments can have a surface area from about0.5 cm² to about 20 cm².

In order to obtain the cells which are used for the skin equivalent ofthe present invention a method for isolating stem/progenitor cells fromthe amniotic membrane of umbilical cord is described herein. The methodcomprises:

(a) separating the amniotic membrane from the other components of theumbilical cord in vitro;

(b) culturing the amniotic membrane tissue obtained in step (a) underconditions allowing cell proliferation; and

(c) isolating the stem/progenitor cells.

For isolation of the cells from umbilical cord, the umbilical cord or apart thereof is usually collected immediately after birth (of a child inthe case of humans) and for transport to the laboratory transferred in amedium that is suitable for handling of mammalian tissue. Examples ofsuch media include, but are not limited to Leibovitz media which arecommercially available from suppliers such as Sigma Aldrich, SaintLouis, Mo. USA or HyClone, Logan, Utah, USA. The umbilical cord is thentypically processed under sterile conditions. Processing of the cordtypically includes removing the blood that has remained on the surfaceor within the blood vessels of the umbilical cord by washing with asuitable buffer such as phosphate buffered saline. The umbilical cord isthen typically reduced to smaller pieces, for example by cutting, andwashed again before separating the amniotic membrane from the othercomponents. In this conjunction, it is noted that it is not necessary toprocess the umbilical cord of a mammalian donor immediately after birthbut it is also possible, to collect the umbilical cord and, optionallyafter washing under sterile conditions and reducing it into smallerpieces, to preserve the umbilical cord or parts thereof bycryo-preservation and to store the so obtained specimen, for example inliquid nitrogen, for later isolation of the cells from the umbilicalcord.

The term “cryo-preservation” is used herein in its regular meaning todescribe a process where cells or whole tissues are preserved by coolingto low sub-zero temperatures, such as (typically) −80° C. or −196° C.(the boiling point of liquid nitrogen). Cryo-preservation can be carriedout as known to the person skilled in the art and can include the use ofcryo-protectors such as dimethylsulfoxide (DMSO) or glycerol, which slowdown the formation of ice-crystals in the cells of the umbilical cord.

The term “stem/progenitor cell” as used herein refers to any cellderived of umbilical cord having the capacities to self-renewindefinitely and to differentiate in multiple cell or tissue types suchas endothelial cells, epithelial cells, fibroblasts, myocytes orneurons. Not every subject which is in need of a skin equivalent canprovide an umbilical cord as source for autologous progenitor/stem cells(i.e. cells obtained from the amniotic membrane of the umbilical cord ofthe same individual the skin equivalent of the present invention islater used for). Accordingly, the use of xenogeneic (i.e. the case ofthe present invention stem/progenitor cells isolated from the amnioticmembrane of the umbilical cord of a species other than human) orallogeneic (i.e. in the case of the present invention stem/progenitorcells isolated from the amniotic membrane of the umbilical cord ofanother human) stem/progenitor cells is also contemplated herein.Furthermore, the cells which are used for the skin equivalent and themethod of its production according to the present invention may bederived of any mammalian species, such as mouse, rat, guinea pig,rabbit, goat, dog, cat, sheep, monkey or human, with cells of humanorigin being preferred in one embodiment.

The term “embryonic stem cell-like properties” refers to the ability ofthe cells derived of umbilical cord that they can—almost like or exactlylike embryonic stem cells—differentiate spontaneously into all tissuetypes, meaning that they are pluripotent stem cells.

The term “amniotic membrane” as used herein refers to the thin innermostmembranous sac enclosing the developing embryo of mammals. Duringpregnancy, the fetus is surrounded and cushioned by a liquid calledamniotic fluid. This fluid, along with the fetus and the placenta, isenclosed within a sac called the amniotic membrane, which also coversthe umbilical cord. The amniotic fluid is important for several reasons.It cushions and protects the fetus, allowing the fetus to move freely.The amniotic fluid also allows the umbilical cord to float, preventingit from being compressed and cutting off the fetus' supply of oxygen andnutrients derived from the circulating blood within the placental bloodvessels. The amniotic sac contains the amniotic fluid, which maintains ahomeostatic environment protecting the fetal environment from theoutside world. This barrier additionally protects the fetus fromorganisms (like bacteria or viruses) that could travel up the vagina andpotentially cause infection.

Media and reagents for tissue culture are well known in the art (cf.,for example, Pollard, J. W. and Walker, J. M. (1997) Basic Cell CultureProtocols, Second Edition, Humana Press, Totowa, N.J.; Freshney, R. I.(2000) Culture of Animal Cells, Fourth Edition, Wiley-Liss, Hoboken,N.J.). Examples of suitable media for incubating/transporting umbilicalcord tissue samples include, but are not limited to, Dulbecco's ModifiedEagle Medium (DMEM), RPMI media, CMRL1066, Hanks' Balanced Salt Solution(HBSS) phosphate buffered saline (PBS), and L-15 medium. Examples ofappropriate media for culturing stem/progenitor cells according to theinvention include, but are not limited to, Dulbecco's Modified EagleMedium (DMEM), DMEM-F12, RPMI media, CMRL1066, EpiLife® medium, andMedium 171. The media may be supplemented with fetal calf serum (FCS) orfetal bovine serum (FBS) as well as antibiotics, growth factors, aminoacids, inhibitors or the like, which is well within the generalknowledge of the skilled artisan.

The method for the isolation of stem/progenitor cells can furthercomprise:

(a″) separating these stem/progenitor cells from the amniotic membranetissue by a enzymatic digestion and/or direct tissue explant techniquebefore cultivation. The term “enzymatic digestion technique” as usedherein means that enzymes are added to cleave the cells from the maintissue mass (here the amniotic membrane of the umbilical cord). Theseparated cells are subsequently collected. The term “direct tissueexplant technique” as used herein means that the tissue is first placedin media without enzymes. Then under careful conditions the cellsseparate from the main tissue mass by itself- and the cells are thenharvested for collection.

Methods for separating cells of a particular tissue or organ bytreatment with enzymes or by direct tissue explant are well known in theart (cf., for example, Pollard, J. W. and Walker, J. M. (1997) BasicCell Culture Protocols, Second Edition, Humana Press, Totowa, N.J.;Freshney, R. I. (2000) Culture of Animal Cells, Fourth Edition,Wiley-Liss, Hoboken, N.J.). Any enzyme catalyzing tissue dissociationmay be used for performing this method. In one example, collagenase isused for that purpose. The enzyme may be used as a crude preparation orin purified form. It may be purified from any prokaryotic or eukaryoticorganism (with Clostridium histolyticum being most preferred) orproduced recombinantly by means of gene technology. Any type ofcollagenase may be employed, i.e. type I, type II, type III, type IV, orany combination thereof. In some examples the use of collagenase type Iis being preferred.

In one example, the invention provides a method for isolatingstem/progenitor cells that have embryonic stem cell-like properties.These cells can ultimately be differentiated into, but not limited to,by morphology, epithelial or mesenchymal stem cells (UCEC and UCMC,respectively).

Accordingly, in another embodiment, the invention provides a skinequivalent wherein the cells derived from stem/progenitor cells aremesenchymal stem cells (UCMC) or epithelial stem cells (UCEC). Thesecells (UCMC and UCEC) are obtained in a method for isolating epithelialand/or mesenchymal stem/progenitor cells, wherein in accordance with theabove disclosure these cells may have embryonic stem cell-likeproperties.

Epithelial stem/progenitor cells (UCEC) include any cells exhibiting aepithelial cell like morphology (i.e. a polyhedral shape) that can bedifferentiated into any type of epithelial cell such as, but not limitedto, skin epithelial cells, hair follicular cells, cornea epithelialcells, conjunctival epithelial cells, retinal epithelial cells, liverepithelial cells, kidney epithelial cells, pancreatic epithelial cells,oesophageal epithelial cells, small intestinal epithelial cells, largeintestinal epithelial cells, lung and airway epithelial cells, bladderepithelial cells or uterine epithelial cells.

Mesenchymal stem/progenitor cells (UCMC) include any cells exhibiting amesenchymal cell like morphology (i.e. a spindle-like shape) that can bedifferentiated into any type of mesenchymal cell such as, but notlimited to, skin fibroblasts, chondrocytes, osteoblasts, tenocytes,ligament fibroblasts, cardiomyocytes, smooth muscle cells, skeletalmuscle cells, adipocytes, cells derived from endocrine glands, and allvarieties and derivatives of neurectodermal cells.

The method for the isolation of stem/progenitor cells can furthercomprise:

(d) culturing the stem/progenitor cells under conditions allowing thecells to undergo clonal expansion.

The term “clonal expansion” (sometimes also referred to as “mitoticclonal expansion”) relates to a process that occurs early in thedifferentiation program of a cell, by which stem/progenitor cells becomecommitted to a particular lineage and then undergo terminaldifferentiation. It is well known in the art that the conditions toinduce clonal expansion of progenitor cells may vary significantlybetween different cell types. Without being limited to a particularmethod, the induction of clonal expansion is generally achieved bycultivating the stem/progenitor cells in a growth medium that has beenoptimized for cell proliferation. Such media are commercially availablefrom many providers. Non-limiting examples of such media areKGM®-Keratinocyte Medium (Cambrex Corporation, New Jersey, USA),MEGM-Mammary Epithelial Cell Medium (Cambrex Corporation, New Jersey,USA), EpiLife® medium (Cascade Biologics Inc., Oregon, USA), Green'sMedium, CMRL 1066 (Mediatech, Inc., Virginia, USA) or Medium 171 (M171;Cascade Biologics Inc., Oregon, USA). Normally, these culture mediumsneed to be supplemented with reagents inducing cell proliferation, suchas growth factors. Such reagents may be admixed in a single solutionsuch as the Human Keratinocyte Growth Supplement Kit (Cascade BiologicsInc., Oregon, USA), to name one example, or may be supplementedindividually. Such reagents include, but are not limited to, growthfactors (such as epidermal growth factor, insulin-like growth factor-1,platelet-derived growth factor-BB, transforming growth factor-β,keratinocyte growth factor (KGF; also referred to as HBGF-7 or FGF-7),TGF-α, amphiregulin for example), hormones (such as a bovine pituitaryextract), hydrocortisone, transferrin and the like in any suitablecombination to induce clonal expansion of a given cell type. The term“clonal expansion” also includes cultivation of the cell in vivo, forexample, by injection of the cells into mammals such as humans, mice,rats, monkeys, apes to name only a few.

The present invention provides a skin equivalent which mimics thenatural composition of the skin with dermal layer and epidermal layer orwith only either one of these two skin layers. For this purpose, cellsof the present invention such as UCMC and UCEC can be differentiatedinto fibroblasts and keratinocytes, respectively. Therefore, theinvention provides in one embodiment a method for the production of askin equivalent comprising:

-   -   providing a scaffold,    -   placing cells derived from stem/progenitor cells isolated from        the amniotic membrane of umbilical cord in or onto said        scaffold, and    -   incubating said scaffold in a first medium, which allows said        cells to proliferate and further differentiate.

As the stem/progenitor cells isolated from the amniotic membrane ofumbilical cord of the present invention have the potential todifferentiate in UCMC and UCEC, as described above, it is preferred insome embodiments to use UCMC and UCEC derived from the stem/progenitorcells isolated from the amniotic membrane of umbilical cord in themethod for the production of a skin equivalent.

In one embodiment of the present invention UCMC extracts obtained asdescribed in Example 20 can be used to induce the growth of cells fromcell lines which would under normal growth conditions not proliferateany or much more because of their chronological age. For example, theUCMC extracts described herein can be used to induce the growth of agedkeratinocytes (asK) which have been obtained from a 60 year old patient.Other cell lines which growth can be induced by use of UCMC extracts aredermal fibroblast cells (NF) as described in Example 20

Thus, the present invention refers to a method of inducing proliferationof aged keratinocytes comprising culturing aged keratinocytes in asuitable growth medium, and adding mesenchymal stem cells (UCMC) of theamniotic membrane of the umbilical cord to the aged keratinocytes toinduce proliferation of the aged keratinocytes. The method can furthercomprise the isolation of the proliferated aged keratinocytes, andapplying them into or onto a scaffold. In one embodiment the agedkeratinocytes can be isolated from a subject who is as old or older than30 years 35 years, 40 years, 50 years, 60 years, 70 years or even morethan 80 years. However, it is also possible to isolate the agedkeratinocytes from a subject that is younger than 30 years.

Depending on the severity of the wound or disorder affecting the skin,it might be sufficient to replace only one layer, i.e. to provide onlyan epidermis layer or to provide only a dermis layer onto whichkeratinocytes forming the epidermis and which already have been culturedor obtained from other sources are placed. To obtain an epidermis layerthe UCEC can be differentiated into keratinocytes, and to obtain adermis layer UCMC can be differentiated into fibroblasts.

Therefore, in the method of the present invention the first mediumincludes a medium adapted for the cultivation of keratinocyte when saidscaffold comprises UCEC in order to proliferate and differentiate saidUCEC in keratinocytes.

In this case, this first medium includes a keratinocyte growth medium, agrowth factor, insulin, transferrin and selenous acid.

The growth factor can be, for example, an epidermal growth factor (EGF),insulin-like growth factor-1, platelet-derived growth factor-BB (PDGFb),transforming growth factor-β, keratinocyte growth factor (KGF), TGF-α oramphiregulin.

The kerationocyte growth medium can be, for example, theKGM®-Keratinocyte Medium (Cambrex Corporation, New Jersey, USA),MEGM-Mammary Epithelial Cell Medium (Cambrex Corporation, New Jersey,USA), EpiLife® medium (Cascade Biologics Inc., Oregon, USA), Green'sMedium, CMRL 1066 (Mediatech, Inc., Virginia, USA), M171 (CascadeBiologics Inc., Oregon, USA), L-15 medium, Dulbecco's Modified EagleMedium (DMEM), DMEM-F12 or RPMI media.

In one embodiment, the first medium adapted for the cultivation ofkeratinocyte when said scaffold comprises UCEC in order to proliferateand differentiate said UCEC in keratinocytes includes a kerationocytegrowth medium, the epidermal growth factor (EGF), insulin, transferrinand selenous acid. In another embodiment, this first medium includes theEpiLife® medium (Cascade Biologics Inc., Oregon, USA), the epidermalgrowth factor (EGF), insulin, transferrin and selenous acid. In yetstill another embodiment, this first medium comprises about 98.8 toabout 99.4% (v/v) EpiLife® medium (Cascade Biologics Inc., Oregon, USA),about 0.2 to about 0.4% (v/v) insulin, about 0.2 to about 0.4% (v/v)transferrin, about 0.2 to about 0.4% (v/v) selenous acid and 10 ng/mlepidermal growth factor (EGF). An example for the keratinocytes obtainedby use of the method of the present invention can be seen in FIG. 18 a.

In another embodiment of the method of the present invention the firstmedium includes a medium adapted for the cultivation of fibroblast whensaid scaffold comprises UCMC in order to proliferate and differentiatesaid UCMC in fibroblasts. In this case, the first medium includes afibroblast growth medium together with fetal calve serum (FCS) or fetalbovine serum (FBS) in order to proliferate and differentiate said UCMCin fibroblasts. The fibroblast growth medium can be, for example, theKGM®-Keratinocyte Medium (Cambrex Corporation, New Jersey, USA),MEGM-Mammary Epithelial Cell Medium (Cambrex Corporation, New Jersey,USA), EpiLife® medium (Cascade Biologics Inc., Oregon, USA), Green'sMedium, CMRL 1066 (Mediatech, Inc., Virginia, USA), M171 (CascadeBiologics Inc., Oregon, USA), L-15 medium, Dulbecco's Modified EagleMedium (DMEM), DMEM-F12 or RPMI media. In one embodiment, the firstmedium for the cultivation of fibroblast when said scaffold comprisesUCMC in order to proliferate and differentiate said UCMC in fibroblastsincludes about 90 to about 95% (v/v) fibroblast growth medium togetherwith about 5 to about 10% fetal or bovine calve serum (FCS). In anotherembodiment, the first medium comprises about 90 to about 95% (v/v)CMRL1066 (Mediatech, Inc., Virginia, USA) and about 5 to about 10% fetalcalve serum (FCS). An example for the fibroblasts obtained by use of themethod of the present invention can be seen in FIG. 18 b.

Once the UCMC or UCEC are fully differentiated to fibroblast andkeratinocytes, respectively, they can be applied to the affected part ofthe mammalian or human body. Sometimes, however, it may be required tosubstitute not only the dermis layer or the epidermis layer but bothskin layers together. This might be the case, for example, when theepidermis layer as well as the dermal layer of the skin is destroyed dueto a burn (full thickness wounds). For this, but also other purposes,the invention provides a method, which includes:

-   -   providing a scaffold,    -   placing UCMC in or onto said scaffold,    -   incubating said scaffold in a first medium adapted for the        cultivation of fibroblast, which allows said UCMC to proliferate        and further differentiate,    -   placing UCEC in or onto said scaffold, and    -   incubating said scaffold in a second medium which allows said        UCEC to proliferate and further differentiate to keratinocytes.

Using the first medium adapted for the cultivation of fibroblast, whichincludes the same components as described above for the first mediumused to differentiate UCMC into fibroblasts, enables a person skilled inthe art to grow a dermis layer comprised of fibroblast in or onto thescaffold. Thereafter, UCEC can be applied in or onto the scaffoldalready including this dermis layer. Using the second medium, whichincludes the same components as described above for the first mediumused to differentiate UCEC into keratinocytes, it is possible to grow anepidermal skin layer onto the first dermis layer. The skin equivalentsof the present invention are thus able to provide a true, morphogenic,multilayer skin equivalent involving UCMC-derived fibroblasts andUCEC-derived keratinocytes. These skin equivalents provide fullthickness dermal regeneration as can be seen in FIG. 19, producingaccelerated healing and reduced scarring.

The time it requires to develop a functional dermal layer out of UCMCdifferentiated into fibroblasts is about 4 to 7 days, whereas once thedermal layer is developed and the UCEC are incorporated into thescaffold, it takes another 8 to 10 days until the epidermal layer hasbeen formed from the UCEC-derived keratinocytes. For autologous culturedskin equivalents produced according to the state of the art it takes atleast 21 to 35 days, depending on size of biopsy, whereas it requiresonly between 12 to 18 days using the method of the present invention.Among other reasons, this is due to the fact that the process can beaccelerated using the method of the present invention as the cells(xenogeneic or allogeneic) used for the skin equivalent of the presentinvention are already provided in the cell bank of the present inventionor in an off-the-shelf cell culture. The initial concentration, whichhas been used for the UCMC and UCEC is in exemplary embodiments within arange of about 1×10⁵ to about 1×10⁶ cells/ml. In one embodiment, aconcentration of about 5×10⁵ UCMC/ml is used for seeding UCMC into ascaffold and 1×10⁶ UCEC/ml for seeding UCEC.

As described in the background section, the dermis of a natural skincontains not only fibroblasts but also contains nerve endings, glands,hair follicles and blood vessels. To further improve the functionalityof the skin equivalent, one embodiment of the method of the presentinvention thus further includes placing cells of one or more cells linesinto or onto the scaffold, which cell lines are able to differentiateinto blood vessels or glands. Some glands produce sweet (sweet glands)in response to heat, whereas other glands produce oil (sebaceous glands)to keep the skin moist and soft. This oil also acts as a barrier againstforeign substances. The blood vessels of the dermis provide nutrients tothe skin and help regulate the body temperature. As these additionalcells fulfil important tasks in the skin, one embodiment of the presentinvention further provides a method, wherein the scaffold furtherincludes vessel endothelial cells or dermal microvascular endothelialcells, to name only a few. In one embodiment the vessel endothelialcells are derived from the umbilical cord of a mammal, and in oneembodiment from the umbilical cord of a human. Non-limiting examples ofdifferent cell lines, which can be used for the method of the presentinvention are, for example, human umbilical vessel endothelial cells(HUVEC) or dermal microvascular endothelial cells (DMEC also referred toas DMVEC), to name only two.

Furthermore, research has shown that the functioning of cells is verymuch influenced by cell extracellular matrix (ECM). As a scaffold, theextracellular matrix forms a three-dimensional pattern which supportscell growth and improves their functionality. Unlike a scaffold asdescribed above, the extracellular matrix consists of natural materialsproduced by the cells itself, whereas the scaffold as described abovecan also include or consist of artificial materials, such as, but notlimited to, porous polycarbonate. Thus, because of the importance of amatrix for cell growth, it is a major goal of tissue engineering torecreate ECM structures that better mimic this matrix surrounding thecells in vivo, in particular to mimic the matrix of in vivo tissue. WeiTan, M. S. and T. A. Desai have shown (Tissue Engineering, 2003, Vol. 9,No. 2, P. 255-267) that native collagen and mixtures of collagen withchitosan or collagen, chitosan and fibronectin can be used to creatematrices for embedding human lung fibroblasts and human umbilical veinendothelial cells therein.

Thus, the present invention further provides a method wherein in or ontosaid scaffold at least one extracellular matrix component is placed.This extracellular matrix component shall mimic the ECM matrix normallyproduced by the cells themselves. Therefore, the ECM component consistsof a material, which can also be found in nature where it is produced bythe cells themselves. Preferably, this at least one extracellular matrixcomponent is placed in or onto the scaffold together with the cellsderived from the stem/progenitor cells described above. If the cells,which are used for the skin equivalent of the present invention and themethod to produce them, are able to produce an ECM component on theirown, the artificial incorporation of an extracellular matrix componentis not required. In one embodiment, UCMC is self-depositing collagen asECM material after being stimulated with ascorbic acid. If the ECMcomponent is added in addition to the cells used in the presentinvention, the extracellular matrix component may be chosen from amaterial such as collagen, elastin, intercellular adhesion molecules,laminin, heparin, fibronectin, proteoglycans, tenascin, fibrillin ormixtures thereof. If collagen is used, it is presently preferred in someembodiments to use type I collagen alone or type I and type III collagenin combination. In one embodiment of the present invention collagen typeI is used.

Also described is a method that further includes preserving the isolatedstem/progenitor cells or differentiated stem/progenitor cells (e.g. UCMCand UCEC) before their use in the skin equivalent of the presentinvention.

Methods and protocols for preserving and storing of eukaryotic cells,and in particular mammalian cells, are well known in the art (cf., forexample, Pollard, J. W. and Walker, J. M. (1997) Basic Cell CultureProtocols, Second Edition, Humana Press, Totowa, N.J.; Freshney, R. I.(2000) Culture of Animal Cells, Fourth Edition, Wiley-Liss, Hoboken,N.J.). Any method maintaining the biological activity of the isolatedstem/progenitor cells such as epithelial or mesenchymal stem/progenitorcells may be utilized in connection with the present invention. In oneexample, the stem/progenitor cells are maintained and stored by usingcryo-preservation.

Accordingly, further described is a progenitor/stem cell derived fromthe amniotic membrane of umbilical cord by means of the above methodsand a cell differentiated from the progenitor/stem cell. In addition, acell bank comprising or consisting of one or more progenitor/stem cellsthat have been isolated as described here is also described. This cellbank of progenitor/stem cells may be autologous to an individual orpooled (the latter for subsequent allogeneic transplantation, forexample), and subsequently can be employed by further differentiationfor regenerative medicine, tissue repair and regeneration, for example.

In accordance with the above, a stem/progenitor cell isolated from theamniotic membrane of umbilical cord by the above described method canalso be comprised in a pharmaceutical composition. The pharmaceuticalcomposition can also include a cell differentiated from thestem/progenitor cell. The pharmaceutical composition can be of any kind,and usually comprises the stem/progenitor cells, a cell differentiatedtherefrom or a cellular secretion or cellular extract thereof togetherwith a suitable therapeutically acceptable carrier/excipient. In case ofa cellular secretion, the desired compound(s) can be used in the form ofthe supernatant into which the compound(s) is/are secreted. In anotherexample, the supernatant might be processed, for example, bypurification and concentration prior to be included in a pharmaceuticalcomposition. In some examples, the pharmaceutical composition is adaptedfor systemic or topical application.

A pharmaceutical composition adapted for topical application may be inliquid or viscous form. Examples thereof include an ointment, a cream,and a lotion and the like. Examples for pharmaceutical compositions thatare suitable for systemic use are liquid compositions, wherein thestem/progenitor cells or the cellular extract are dissolved in a bufferthat is acceptable for injection or infusion, for example. Thepreparation of such pharmaceutical compositions is within the knowledgeof the person skilled in the art and described in Gennaro, A. L. andGennaro, A. R. (2000) Remington: The Science and Practice of Pharmacy,20th Ed., Lippincott Williams & Wilkins, Philadelphia, Pa., for example.

Accordingly, a method of treating a subject having a disorder isdescribed. This method comprises administering to the subject aneffective amount either of a stem/progenitor cell isolated as explainedherein or of a cellular extract derived from such a cell.

In principle, any condition or disorder which is suitable for beingtreated by means of stem cells/progenitor cells can be treated with acell or a cellular extract. It is also possible to differentiate cellsinto a desired type of cell, for example, but not limited to, a skincell, a bone or cartilage cell, s hepatocyte, an antigen-producing cell,a hormone producing cell such as a beta islet insulin producing cell,and using the differentiated cell therapeutically.

Thus, the present invention also refers to a method for generating aninsulin-producing cell, comprising:

-   -   cultivating cells derived from stem/progenitor cells isolated        from the amniotic membrane of umbilical cord, and    -   proliferating and differentiating said cells in a suitable        cultivation medium into β-islet cells.

In one embodiment, the cells derived from stem/progenitor cells aremesenchymal stem cells (UCMC) or epithelial stem cells (UCEC), which canbe further differentiated into insulin secreting β-islet cells byincluding nicotinamide into the cell culture medium.

Besides nicotinamide, the cultivation medium may further include agrowth medium for the cultivation of β-islet cells. The cultivationmedium may also include a growth factor or fetal serum. The fetal serummay, for example, be of calve or bovine origin. In one embodiment, thecultivation medium can further include insulin, transferrin and selenousacid. The growth factor can, for example, be, but is not limited to,epidermal growth factor (EGF), insulin-like growth factor-1,platelet-derived growth factor-BB (PDGFb), transforming growth factor-β,keratinocyte growth factor (KGF), TGF-α or amphiregulin. The growthmedium for the cultivation of β-islet cells can, for example, be, but isnot limited to, KGM®-Keratinocyte Medium (Cambrex Corporation, NewJersey, USA), MEGM-Mammary Epithelial Cell Medium (Cambrex Corporation,New Jersey, USA), EpiLife® medium (Cascade Biologics Inc., Oregon, USA),Green's Medium, CMRL 1066 (Mediatech, Inc., Virginia, USA), M171(Cascade Biologics Inc., Oregon, USA), L-15 medium, Dulbecco's ModifiedEagle Medium (DMEM), DMEM-F12 or RPMI media.

In one embodiment of the present invention the media described inExample 15 are used to differentiate UCMC or UCEC into β-islet cells.

In another embodiment, the method includes isolating insulin produced bythe β-islet cells, which can afterwards be used for the treatment, e.g.,of insulin dependent diabetes mellitus (IDDM), e.g. in a mammal. Themammal can, for example, be a human, a cat, a dog, a sheep, a horse or apig. The isolation of the insulin can be carried out for exampleaccording to, but not limited to, the method described by Jones P. M.and Saermark, T. et al. (Anal Biochem. 1987 October; 166(1):142-9).

Accordingly, the present invention is also directed to aninsulin-producing cell obtained by a method for generating an insulinproducing cell according to the present invention. The present inventionis also directed to a method of treating a disorder associated with animbalance in the insulin level, comprising administering to a mammal aninsulin-producing cell obtained by the method of the present invention.The mammal can, for example, be a human, a cat, a dog, a sheep, a horseor a pig. An example of such a disease is insulin dependent diabetesmellitus (IDDM).

In a further embodiment of the present invention, it is provided amethod of generating a dopamin and tyrosin hydroxylase producing cell,comprising cultivating cells derived from stem/progenitor cells isolatedfrom the amniotic membrane of umbilical cord, preferably UCMC, andproliferating and differentiating said cells in a suitable cultivationmedium into dopamin and tyrosin hydroxylase (TH) producing cells.Dopamine functions as a neurotransmitter, activating dopamine receptors.Dopamine is also a neurohormone released by the hypothalamus. Its mainfunction as a hormone is to inhibit the release of prolactin from theanterior lobe of the pituitary. Dopamine can be supplied as a medicationthat acts on the sympathetic nervous system, producing effects such asincreased heart rate and blood pressure. Tyrosine hydroxylase is theenzyme responsible for catalysing the conversion of L-tyrosine, an aminoacid, to dihydroxyphenylalanine (DOPA), a precursor to Dopamine in theprocess the body uses to synthesise adrenaline (epinephrin). Thus, in afurther embodiment, the method further comprises isolating dopaminand/or tyrosin hydroxylase produced by the dopamin and tyrosinhydroxylase producing cells derived from UCMC.

The present invention also provides a method of generating humanleukocyte antigen G (HLA-G). Human leukocyte antigen (HLA)-G is a majorhistocompatibility complex class I antigen, which is referred to asnonclassical because it displays a tissue-restricted distribution in theplacenta, a reduced cytoplasmic domain, a limited polymorphism, andseveral isoforms. The HLA-G antigen is thought to play an essential roleduring pregnancy by protecting the semi-allogeneic fetus fromrecognition and destruction by maternal immune cells. HLA-G has beenimplicated in various immune-mediated diseases and conditions, likeorgan-, cell transplantation and auto-immune diseases. Examples for suchautoimmune diseases are multiple sclerosis, rheumatoid arthritis, type Idiabetes mellitus, psoriasis, thyroid diseases, systemic lupuserythematosus, scleroderma or celiac disease. Thus, the presentinvention provides a method for generating a human leukocyte antigen G(HLA-G) producing cell, comprising cultivating cells derived fromstem/progenitor cells isolated from the amniotic membrane of umbilicalcord, and proliferating and differentiating this cells in a suitablecultivation medium into HLA-G producing cells. HLA-G producing cells canbe generated either from UCEC or UCMC. With the method of the presentinvention it was shown for the first time that naïve UCEC express andproduce HLA-G. Surprisingly, for this method, a specific induction ofUCEC for the production of HLA-G is not necessary (see Example 19).

Other disorders, which can be treated using the stem/progenitor cellsdescribed herein, are selected from the group consisting of neoplasticdisease, accelerated skin aging and skin disorders, tissue disorders,visceral endocrine deficiencies, and neural disorders.

The tissue disorder to be treated can be a congenital or an acquiredtissue deficiency. Examples of visceral endocrine deficiency that can betreated with a stem/progenitor cell or a cell derived therefrom include,but are not limited to, testosterone deficiency, anemia, hypoglycemia,hyperglycemia, pancreatic deficiency, adrenal deficiency, and thyroiddeficiencies.

Examples of neural disorders that can be treated include, but are notlimited to, Alzheimer's disease, Parkinson's disease, Jacob Kreutzfeld'sdisease, Lou Gehrig's disease, Huntington's disease and neuralneoplastic conditions.

The present invention is also directed to the use of mesenchymal stemcells (UCMC) isolated from the amniotic membrane of the umbilical cordfor the production of osteoblasts (see Example 10) which are used forthe treatment of damages of a bone, or for the production ofchondrocytes (see Example 17) which are used for the treatment ofdamages of cartilage.

Furthermore, the present invention also provides a method of generatinghepatocytes, comprising cultivating cells derived from stem/progenitorcells isolated from the amniotic membrane of umbilical cord, preferablyUCEC, and proliferating and differentiating said cells in a suitablecultivation medium into hepatocytes. The suitable cultivation mediumcontains oncostatin-M for inducing the differentiation into hepatocytes.Oncostatin-M (OSM) is a pleitropic cytocine that belongs to theInterleukin-6 group of cytokines. Of these cytokines it most closelyresembles leukemia inhibitory factor in both structure and function.However it is as yet poorly defined and is proving important in liverdevelopment, haematopoeisis, inflammation and possibly CNS development.

In line with the above discussion, the invention also refers to a methodof treating a wound or a skin disorder including applying the skinequivalent of the present invention with a wound or a skin disorder.Accordingly, a skin equivalent of the present invention which has beenobtained by a method of the present invention can be used for themanufacture of a pharmaceutical composition. The present invention isfurther directed to a pharmaceutical composition thus obtained for thetreatment of burned skin, an ulcer, radiation and diabetic wounds. Theinvention is also directed to a cell bank comprising a skin equivalentof the present invention.

An example of a skin disease is a wound or a damaged part of the skin,for example, sun burned skin. Also aging of the skin is considered to bea skin disease herein. Topical or similar delivery of stem/progenitorcells or cellular extracts thereof, for example, as a constituent inlotions or creams or any other suitable vehicle may thus be used forrepair of sun damaged skin and in addition may slow also down the agingprocess of skin (anti-aging properties) by replenishing, and thusfortifying, deficient growth factors and related peptide elements,without which skin aging would be accelerated. A skin equivalent of thepresent invention can be used accordingly. The stem/progenitor cells mayalso migrate to injured regions of the body such as surface wounds toform the necessary required cellular elements necessary for the localreparative processes (cf. The Journal of Immunology, 2001, 166:7556-7562; or International Journal of Biochemical and Cell Biology2004; 36: 598-606).

The neoplastic disease may be cancer, in particular as recent studieshave demonstrated that stem cells may selectively target neoplastictumor tissue (Journal of the National Cancer Institute 2004; 96 (21):1593-1603) allowing for directed delivery of antineoplastic agents suchas interferon to neoplastic foci. The cancer can be any kind of cancer,including those cancers that are able to form solid tumors, ranging fromskin cancer to cancer of the internal organs. Examples of cancers to betreated include, squamous cell carcinoma, breast ductal and lobularcarcinoma, hepatocellular carcinoma, nasopharyngeal carcinoma, lungcancer, bone cancer, pancreatic cancer, skin cancer, cancer of the heador neck, cutaneous or intraocular malignant melanoma, uterine cancer,ovarian cancer, rectal cancer, cancer of the anal region, stomachcancer, colon cancer, breast cancer, testicular cancer, uterine cancer,carcinoma of the fallopian tubes, carcinoma of the endometrium,carcinoma of the cervix, carcinoma of the vagina, carcinoma of thevulva, Hodgkin's Disease, non-Hodgkin's lymphoma, cancer of theesophagus, cancer of the small intestine, cancer of the endocrinesystem, cancer of the thyroid gland, cancer of the parathyroid gland,cancer of the adrenal gland, sarcoma of soft tissue, cancer of theurethra, cancer of the penis, prostate cancer, chronic or acuteleukemias, solid tumors of childhood, lymphocytic lymphoma, cancer ofthe bladder, cancer of the kidney or ureter, renal cell carcinoma,carcinoma of the renal pelvis, neoplasm of the central nervous system(CNS), primary CNS lymphoma, tumor angiogenesis, spinal axis tumor,brain stem glioma, pituitary adenoma, Kaposi's sarcoma, epidermoidcancer or any combination of such cancers, including disseminated(metastasising) forms thereof. In case of treatment of a neoplasticdisease the umbilical cord amnion derived stem cells and/or theircellular extracts described herein can be administered systemically bothas a direct treatment and/or as a carrier vehicle. In the latter case ofanti-neoplastic tumor therapy, the cells comprise an anti-neoplasticagent.

In another pharmaceutical use, stem/progenitor cells can be used forgene therapy. For this purpose, the cells can be transformed with anucleic acid encoding the protein that is to be produced in the cells.The nucleic acid can be introduced into a cells of the invention usingany of the various methods that are well known to the skilled person,for example, using a viral vector and/or a lipid containing transfectioncomposition such as IBAfect (IBA GmbH, Göttingen, Germany), Fugene (F.Hoffmann-LaRoche Ltd., Basel, Switzerland), GenePorter® (Gene TherapySystems), Lipofectamine (Invitrogen Corporation, California, USA),Superfect (Qiagen, Hilden, Germany), Metafecten (Biontex, Munich,Germany) or those ones described in the PCT application WO 01/015755).In a related embodiment, the stem/progenitor cells and cells derivedtherefrom, after being transformed with a nucleic acid encoding apolypeptide of choice, can be used of recombinantly producing thispolypeptide.

As mentioned above, stem cell extracts are rich in a variety of growthfactors and peptides that are relevant for normal tissue physiology.Such growth factors and/or peptides may be deficient in exposed parts ofthe body, such as the skin, which is the surface layer of all humanbeings protecting the body from external elements for the maintenance ofinternal homeostasis. Therefore, stem/progenitor cells or cellularextracts thereof are suitable for the treatment and/or maintenance ofinternal homeostasis.

Furthermore and in line with the above description, the stem/progenitorcells and cells derived therefrom can be used for the production of anybiological molecule. The biological molecule can be, for instance, anymolecule that is naturally produced in the cells or a molecule thecoding nucleic acid of which has been introduced into the cells viarecombinant DNA technology. Examples of molecules that can be producedby the cells include, but are not limited to, a protein such as acytokine, a growth factor such as insulin-like growth factor (IGF),epidermal growth factor (EGF), transforming growth factor beta(TGF-beta), Activin A, a bone morphogenetic protein (BMP), PDGF or ahormone as insulin or erythropoietin or a transporter protein suchtransferrin, a peptide such a growth factor or hormone (e.g. luteinichormone (LSH), follicle stimulating hormone (FSH)), a small organicmolecule such as a steroid hormone, an oligo- or polysaccharide, forexample, heparin or heparan sulfate (cf., example WO 96/23003, or WO96/02259 in this regard), a proteoglycan, a glycoprotein such ascollagen or laminin, or a lipid, to name only a few.

Mucin, which is a glycoprotein, is a complex molecule that can be foundin mucous secrets of most epithelial layers (e.g. saliva, gastric juice,chyle, bronchial juice). Mucin carries out lube- and protectivefunctions (e.g. transport of chime, buffering excessive gastric acid,lube function within the synovial fluid of joints). Due to its complexstructure and its high molar mass (of about 1-50 million Dalton) it isnormally difficult to isolate mucin molecules in their native form.

Thus, the present invention further provides a method for the generationof a mucin-producing cell comprising:

-   -   placing umbilical cord amniotic membrane epithelial stem cells        (UCEC) in a container (e.g. culture flask, petri dish), and    -   incubating said UCEC in a medium adapted for the cultivation of        secretory cells.

These mucin-producing cells cannot only be used to isolate mucin fromthe cell culture media but also to use these cells in a method of thepresent invention comprising contacting a tissue comprising cellsaffected by smoke with a mucin-producing cell generated by the method ofthe present invention. These affected cells may be cells of therespiratory tracts, e.g. the lung, or the ocular surface.

Furthermore, the mucin-producing cells obtained by the method of thepresent invention can be used for the treatment of a synovial cellsarcoma, a smoke inhalation injury or ocular surface injury. Themucin-producing cells obtained by the method of the present inventioncan further be used for oesophagus and airway track tissue engineering,for cosmetic applications or as gene/protein delivery system.

To differentiate UCEC as described herein into mucin-producing cells,the invention further provides a medium, wherein said medium includes agrowth medium for the cultivation of mucin-producing cells, insulin,transferrin, selenous acid and a growth factor.

The growth factor can, for example, be but is not limited to, epidermalgrowth factor (EGF), insulin-like growth factor-1, platelet-derivedgrowth factor-BB (PDGFb), transforming growth factor-β, keratinocytegrowth factor (KGF), TGF-α or amphiregulin.

The growth medium for the cultivation of mucin-producing cells can, forexample, be, but is not limited to, KGM®-Keratinocyte Medium (CambrexCorporation, New Jersey, USA), MEGM-Mammary Epithelial Cell Medium(Cambrex Corporation, New Jersey, USA), EpiLife® medium (CascadeBiologics Inc., Oregon, USA), Green's Medium, CMRL1066 (Mediatech, Inc.,Virginia, USA), M171 (Cascade Biologics Inc., Oregon, USA), L-15 medium,Dulbecco's Modified Eagle Medium (DMEM), DMEM-F12 or the RPMI media.

In one embodiment the medium adapted for the cultivation of amucin-producing cell includes a growth medium for the cultivation ofmucin-producing cells, the epidermal growth factor (EGF), insulin,transferrin and selenous acid.

In still another embodiment, the medium adapted for the cultivation of amucin-producing cell includes about 98.8 to about 99.4% (v/v) of agrowth medium for the cultivation of mucin-producing cells, about 0.2 toabout 0.4% (v/v) insulin, about 0.2 to about 0.4% (v/v) transferrin,about 0.2 to about 0.4% (v/v) selenous acid and about 10 ng/ml epidermalgrowth factor (EGF).

In another embodiment, the medium adapted for the cultivation of amucin-producing cell comprises about 98.8 to about 99.4% (v/v) CMRL1066(Mediatech, Inc., Virginia, USA) or M171 (Cascade Biologics Inc.,Oregon, USA), together with about 0.2 to about 0.4% (v/v) insulin, about0.2 to about 0.4% (v/v) transferrin, about 0.2 to about 0.4% (v/v)selenous acid and about 10 ng/ml epidermal growth factor (EGF).

Mucin-producing cells which are produced by the method of the presentinvention can be defined by a Mucin-clot-test (see Example 16). Thistest is also described by Corfield A. P., Glycoprotein method andprocotols: The Mucins, page 29-65. Humana Press 2000; Gatter R. A. andSchumacher R. H., A practical handbook of join fluid analysis, page59-63, Lea & Febiger, 1991, the entire contents of which is incorporatedherein by reference. This test is an assessment of the quality andquantity of mucin produced by UCEC cultured in cell culture media asdefined above. Briefly, in this test media of cell cultures in whichUCEC cells have been incubated according to the method of the presentinvention is expelled into 7 N glacial acetic acid. The acetic acidcauses the mucin to form a clot. Media containing mucin will appear asclear fluid with a tight, ropy clot. Thus, in one embodiment a mucinproducing cell as used herein refers to a cell which yields in apositive result when examined using the test and the conditions asdescribed in Example 16.

In accordance with recent approaches (see, for example, Amit, M et al.,Human feeder layers for human embryonic stem cells, Biol Reprod 2003;68: 2150-2156), the stem/progenitor cells described here can be used asfeeder layer for the cultivation of other embryonic stem cells, inparticular human embryonic stem cells. In one of these embodiments thecells are preferably of human origin, since using human cells as feederlayer minimizes the risk of contaminating the cell culture withanimal-derived components such as animal pathogens or immunogens. Inthis respect, it is to be noted that the stem/progenitor cells and cellsderived therefrom can be cultivated under serum free conditions.Accordingly, employing the cells as feeder layer and cultivating thecell culture under with serum free media as the one described hereinlater, or in Draper et al. (Culture and characterization of humanembryonic stem cell lines, Stem Cells Dev 2004, 13:325-336) or in theInternational patent application WO 98/30679, for example.

In this connection, it is noted that in transplantation surgery andcell-based therapy high quantities of low passage cells with a minimalproportion of senescent cells (i.e., large proportion of high qualitycells) are crucial and are required to be derived within the shortestpossible time during cell expansion. For example, mesenchymal stem cellsfrom bone marrow and cord blood are low in quantity and thereforerequire expansion over many passages for a long period of time in orderto achieve the sufficient number of cells required for cell transplant.The high passage cells however tend to deteriorate in quality and maylead to cell senescence or cancerous transformation. It has been foundhere that high quantities of stem/progenitor cells can be obtained bylow passage numbers using a repetitive explanation technique. Thus amethod of cultivating stem/progenitors cells is described, wherein thismethod comprises:

Obtaining a tissue explant from the amniotic membrane of umbilical cord;

Cultivating the tissue explant in suitable cultivation media andcultivation conditions over a suitable period of time,

Optionally exposing the tissue explant to fresh cultivation media andcontinuing the cultivation under suitable conditions over a suitableperiod of time (cf., FIG. 15).

The cultivation can be carried out in for as many cycles (passages) aswanted and be stopped once the desired number of cells has beenobtained. Exposing the tissue explant to fresh cultivation can becarried out by removing the used cell cultivation medium from the vesselused for growing the cells and adding fresh media to that vessel.Instead of replacing the media in the used vessel, exposing to freshcultivation media can be achieved by transferring the tissue explant toa new vessel which is filled with cultivation media. The tissue explantused for cultivation/propagation of the cells can be obtained by anysuitable method, for example by the “direct tissue explant technique” asexplained above (in which the tissue is first placed in media withoutenzymes, and then under careful conditions the cells separate from themain tissue mass by itself, and the cells are then harvested forcollection).

The cultivation of the tissue explants can be carried out in any mediathat is suitable for cultivation of mammalian cells. Examples includethe conventional and commercially available media that are given abovewith respect to the cultivation or the clonal expansion of thestem/progenitor cells and cells derived therefrom such as, but notlimited to, KGM®-Keratinocyte Medium (Cambrex Corporation, New Jersey,USA), MEGM-Mammary Epithelial Cell Medium (Cambrex Corporation, NewJersey, USA) EpiLife® medium (Cascade Biologics Inc., Oregon, USA),Medium 171 (Cascade Biologics Inc., Oregon, USA), DMEM, DMEM-F12 or RPMImedia. The cultivation is typically carried out at conditions(temperature, atmosphere) that are normally used for cultivation ofcells of the species of which the cells are derived, for example, at 37°C. in air atmosphere with 5% CO₂. In one embodiment, the cultivation iscarried out using serum free, in particular bovine serum free media. Thecultivation (in one passage) is performed for any suitable time thecells need for growth, typically, but by no means limited to, for about1 to several days, for example to about 7 or about 8 days.

The inventions illustratively described herein may suitably be practicedin the absence of any element or elements, limitation or limitations,not specifically disclosed herein. Thus, for example, the terms“comprising”, “including”, “containing”, etc. shall be read expansivelyand without limitation. Additionally, the terms and expressions employedherein have been used as terms of description and not of limitation, andthere is no intention in the use of such terms and expressions ofexcluding any equivalents of the features shown and described orportions thereof, but it is recognized that various modifications arepossible within the scope of the invention claimed. Thus, it should beunderstood that although the present invention has been specificallydisclosed by preferred embodiments and optional features, modificationand variation of the inventions embodied therein herein disclosed may beresorted to by those skilled in the art, and that such modifications andvariations are considered to be within the scope of this invention.

The invention has been described broadly and generically herein. Each ofthe narrower species and subgeneric groupings falling within the genericdisclosure also form part of the invention. This includes the genericdescription of the invention with a proviso or negative limitationremoving any subject matter from the genus, regardless of whether or notthe excised material is specifically recited herein.

Other embodiments are within the following claims and non-limitingexamples. In addition, where features or aspects of the invention aredescribed in terms of Markush groups, those skilled in the art willrecognize that the invention is also thereby described in terms of anyindividual member or subgroup of members of the Markush group.

EXAMPLES Example 1: Collection of Umbilical Cord Tissue

Umbilical cord tissue is collected immediately after delivery of thechild. The specimen is rinsed clean and immediately transferred into a500 ml sterile glass bottle containing culture transport medium (L-15medium supplemented with 50 IU/ml penicillin, 50 μg/ml streptomycin, 250μg/ml fungizone, 50 μg/ml gentamicin; all reagents purchased fromInvitrogen) prior to transport to the laboratory. In the laboratory,stem cell extraction is conducted in a laminar flow hood under sterileconditions. The specimen is first transferred to a sterile stainlesssteel tray. All remaining blood in the cord vessels is removed bymultiple syringing washes using warm phosphate-buffered saline (PBS)supplemented with 5 IU/ml heparin (from Sigma-Aldrich, Missouri, USA).Plain PBS without heparin is used in the final washes. The umbilicalcord tissue specimen is then cut into pieces 2 cm in length andtransferred into 10 cm diameter cell culture dishes, where furtherwashing and disinfection is performed with 70% ethanol followed bymultiple washes using PBS containing an antibiotic mixture (50 IU/mlpenicillin, 50 μg/ml streptomycin, 250 μg/ml fungizone, 50 μg/mlgentamicin; all purchased from Invitrogen Corporation, California, USA)until the solution becomes clear.

Example 2: Cell Separation/Cultivation

Dissection of umbilical cord tissue is first performed to separate theumbilical cord amniotic membrane from Wharton's jelly (i.e. the matrixof umbilical cord) and other internal components. The isolated amnioticmembrane is then cut into small pieces (0.5 cm×0.5 cm) for cellisolation. Explant is performed by placing the pieces of umbilical cordamniotic membrane on tissue culture dishes at different cell cultureconditions for isolation of either epithelial or mesenchymal stem cells.

For mesenchymal cell separation/cultivation, the explants were submergedin 5 ml DMEM (Invitrogen Corporation, California, USA) supplemented with10% fetal bovine serum (Hyclone, Utah, USA) (DMEM/10% FBS) andmaintained in a CO₂ cell culture incubator at 37° C. The medium waschanged every 2 or 3 days. Cell outgrowth was monitored under lightmicroscopy. Outgrowing cells were harvested by trypsinization (0.125%trypsin/0.05% EDTA) for further expansion and cryo-preservation usingDMEM/10% FBS.

For epithelial cell separation/cultivation, cell culture plasticsurfaces were coated with collagen 1/collagen 4 mixtures (1:2) beforeplacing the tissue samples on the surface. The tissue samples weresubmerged in 5 ml EpiLife medium or Medium 171 (both from CascadeBiologics Inc., Oregon, USA). The medium was changed every 2 or 3 days.Cell outgrowth from tissue culture explants was monitored under lightmicroscopy. Outgrowing cells were harvested by trypsinization (0.125%trypsin/0.05% EDTA) using EpiLife® medium or Medium 171.

For the enzymatic extraction method of cells, umbilical cord amnioticmembrane was divided into small pieces of 0.5 cm×0.5 cm and digested in0.1% (w/v) collagenase type I solution (L. Hoffmann-LaRoche Ltd., Basel,Switzerland) at 37° C. for 6 hours. The samples were vortexed every 15min for 2 min. Cells were harvested by centrifugation at 4000 rpm for 30min. Two different approaches were employed to isolate either epithelialor mesenchymal stem cells.

For isolation of epithelial stem cells, cell pellets were resuspended inEpiLife® medium or Medium 171 (both from Cascade Biologics Inc., Oregon,USA) supplemented with 50 μg/ml insulin-like growth factor-1 (IGF-1), 50μg/ml platelet-derived growth factor-BB (PDGF-BB), 5 μg/ml transforminggrowth factor-β (TGF-β1), and 5 μg/ml insulin (all obtained from R&DSystems, Minneapolis, USA), counted and seeded on 10 cm tissue culturedishes pre-coated with collagen 1/collagen 4 mixtures (1:2; BectonDickinson, New Jersey, USA) at density of 1×10⁶ cells/dish. After 24hours, attached cells were washed with warm PBS and medium was replacedwith supplement-added EpiLife® medium or Medium 171. The medium waschanged every 2 or 3 days. Cell growth and expanding clonal formationwas monitored under light microscopy. At a confluence of about 70%,cells were sub-cultured by trypsinization (0.125% trypsin/0.05% EDTA)for further expansion and cryo-preservation.

For isolation of mesenchymal stem cells, cell pellets were resuspendedin PTT-4 medium, counted and seeded on 10 cm tissue culture dishes atdensity of 1×10⁶ cells/dish. The culture medium was changed every 2 or 3days. Cell growth and expansion was monitored under light microscopy. Ata confluence of about 90%, cells were sub-cultured as outlined above.

For cultivation of epithelial and mesenchymal stem cells on feederlayer, umbilical cord lining membrane was digested by collagenasetreatment, counted and seeded on 10 cm tissue culture dishes coated withlethally irradiated or Mitomycin C treated 3T3 fibroblasts (feederlayer) in Green's medium. The culture medium was changed every 2 or 3days. Colony formation was monitored under light microscopy andphotographed.

Example 3: Identification of Stem/Progenitor Cells

Epithelial cells: FIG. 1 shows pictures of outgrowing epithelial cellsfrom umbilical cord amniotic membrane prepared by the method usingtissue explant (40× magnification). Pictures were taken at day 2 (FIG.1A) and day 5 (FIG. 1B, C) of tissue culture. Cell morphology analysisdemonstrated polyhedral shaped epithelial-like cells. Enzymaticdigestion of the umbilical cord segments yielded similar (FIG. 2),epithelial cells at day 2 (FIG. A, C) and day 5 (FIG. B, D) (40×magnification). FIG. 7 shows pictures of colony formation of epithelialstem cells from umbilical cord amniotic membrane cultured on feederlayer using Green's method (40× magnification). A colony of polyhedralshaped epithelial-like cells expanded rapidly from day 3 to day 7.

Mesenchymal cells: Outgrowth of mesenchymal cells explanted fromumbilical cord amniotic membrane was observed as early as 48 hours afterplacement in tissue culture dishes using CMRL-1066 supplemented with 10%fetal calf serum (FCS) (or PTT-4 medium) as culture medium (FIG. 3A, C)(40× magnification). The cells were characterized by their spindleshaped morphology, and migrated and expanded both easily and quickly invitro, closely resembling fibroblasts (FIG. 3B, D) (40× magnification).Similar observations were noted in the cell group isolated bycollagenase enzymatic digestion (FIG. 4). FIG. 4A shows mesenchymalcells isolated from umbilical cord amniotic membrane at day 2. Cellproliferation was observed at day 5 (FIG. 4B) (40× magnification). FIGS.6 and 8-1 show pictures of colony formation of mesenchymal stem cellsfrom umbilical cord amniotic membrane cultured on non-feeder layer (FIG.6) and feeder layer condition (FIG. 8-1, using a 3T3 feeder layer) inPTT-4 medium (40× magnification). The colonies of elongated shapedfibroblastic-like cells expanded rapidly from day 3 to day 7. It isnoted in this respect, that the 3T3 feeder layer normally suppresses thegrowth of mesenchymal cells as human dermal fibroblasts. Once again,this indicates a difference in the behavior of the mesenchymal cells ofthe invention as compared to more differentiated counterparts.

In further experiments the colony forming ability of the mesenchymalcells of the invention (UCMC) was studied. For colony forming efficiencyassay, 100-200 single cells were seeded in 100 mm tissue culture dishesor T75 flasks without feeder layers. Cells were maintained in DMEM/10%FCS for 12 days. Single colony formation was monitored under theinverted light microscope (experiment was carried out in duplicate,experiments termed UCMC-16 and UCMC-17 in FIG. 8-2). Microphotographswere sequentially taken. At day 12, colonies were fixed and stained withRhodamine. UCMC colony forming units were seen (FIG. 8-2). The multiplelarge colonies observed, indicated self-renewal of CLSC in-vitro (FIG.8-2).

Western blot analysis (FIG. 9) shows that mesenchymal stem cells fromumbilical cord amniotic membrane (UCMC) and umbilical cord epithelialcells (UCEC) isolated in accordance with the invention expressed thePOU5f1 gene which encodes the transcription factor Octamer-4 (Oct-4) aspecific marker of embryonic stem cells (cf. Niwa, H., Miyazaki, J., andSmith, A. G. (2000). Nat. Genet. 24, 372-376) (FIG. 9-1). Furtherresults shown in FIGS. 9.1a and 9.1b confirm the expression of Oct-4 inUCMC cells. Briefly, in the experiments leading to the resultsillustrated in FIGS. 9.1a and 9.1b UCMC were seeded in 100 mm tissueculture dishes at a density of 50 cells/culture dish. The cells werethen maintained in PTT-4 (for the composition of PTT-4 see Example 12)for 10 days until some colonies were visible. The colonies were thenfixed and incubated with an anti-Oct-4 antibody (ES Cell Marker SampleKit (Catalog No. SCR002); Chemicon, Temecula, Calif.). One dish (No. 5in FIG. 9.1a ) served as negative control with a secondary antibodystaining only. FIG. 9.1b illustrates the morphology of stained UCMCcells that were grown in the above mentioned PTT-4 medium. Thus, thisanalysis indicates the embryonic-like properties of these stem cells.These mesenchymal and epithelial cells also expressed Bmi-1, a markerthat is required for the self-renewal of adult stem cells (cf., Park etal., J. Clin. Invest. 113, 175-179 (2004) (FIG. 9-27) as well asleukemia inhibitory factor (LIF) (FIG. 9-28) that is considered tomaintain the pluripotency of stem cells and embryonic cells and hasthus, for example been used for isolation and expansion of human neuralstem cells. These cells also highly expressed the other growth factorssuch as connective tissue growth factor (CTGF) (FIGS. 9-6, 9-7),vascular endothelial growth factor (VEGF) (FIGS. 9-10, 9-11),placenta-like growth factor PLGF (FIGS. 9-4, 9-5), STAT3 (FIGS. 9-2,9-3), stem cell factor (SCF) (FIG. 9-16), Hepatoma-derived Growth Factor(HDGF) (FIGS. 9-14, 9-15), Fibroblast Growth Factor-2 (FGF-2) (FIGS.9-12, 9-13), Platelet-derived Growth Factor (PDGF) (FIGS. 9-8, 9-9),alpha-Smooth Muscle Actin (α-SMA) (FIG. 9-17), Fibronectin (FIGS. 9-18,9-19), Decorin (FIG. 9-20), Syndecan-1,2,3,4 (FIGS. 9-21 to 9-26). InFIG. 9, the expression of these genes is compared to human dermalfibroblasts, bone marrow mesenchymal cells (BMSC) and adipose-derivedmesenchymal cells (ADMC). FIG. 9-29 shows Western blot data of thesecretion of leukemia inhibitory factor (LIF) by both UCEC and UCMC.FIG. 9-30 shows highly secreted Activin A and Follistatin (both of whichproteins are well known to promote tissue repair and regeneration,enhanced angiogenesis, and maintain embryonic stem cell culture, so thatexpression of the respective genes is a sign for the embryonicproperties and ability of the cells to differentiate) detected ELISAassay (FIG. 9-30) in supernatants of umbilical cord mesenchymal andepithelial stem cell culture in comparison with bone marrow, adiposederived stem cells, human dermal fibroblasts and epidermalkeratinocytes. Also these results indicate that the cells of theinvention are promising candidates in therapeutic application of thesecells areas such as regenerative medicine, aging medicine, tissue repairand tissue engineering. In addition, FIGS. 9-29 and 9-30 show thecapability of the cells to secret an expression product into the culturemedium.

Mesenchymal cells were further characterized by analysis of secretedcytokines and growth factors in comparison with human bone-marrowmesenchymal stem cells. The umbilical cord epithelial stem cells (UCEC)were analysed in comparison with human epidermal keratinocytes. Thisanalysis was carried out as follows: Briefly, UCMC, UCEC, dermalfibroblasts, bone-marrow mesenchymal cells, epidermal keratinocytes werecultured in growth media until 100% confluence (37° C., 5% CO₂) and thensynchronized in starvation medium (serum-free DMEM) for 48 hours. Thenext day, the medium was replaced the next against fresh serum-free DMEMand the cells then were cultivated for another 48 hours. Conditionedmedia were collected, concentrated and analyzed using a Cytokine Array(RayBiotech Inc., Gorgia, USA).

The results of this analysis show that UCMC secrete Interleukin-6(IL-6); (MCP1); hepatocyte growth factor (HGF); Interleukin-8 (IL8);sTNFR1; GRO; TIMP1; TIMP2; TRAILR3; uPAR; ICAM1; IGFBP3; IGFBP6 (FIG.11), whereas UCEC secrete IGFBP-4; PARC; EGF; IGFBP-2; IL-6; Angiogenin;GCP-2; IL1Rα; MCP-1; RANTES; SCF; TNFβ; HGF; IL8; sTNFR; GRO; GRO-α;Amphiregulin; IL-1R4/ST2; TIMP1; TIMP2; uPAR; VEGF (FIG. 12).

Accordingly, this shows that both cells types secrete large amounts ofcytokines and growth factors that play important roles in developmentalbiology, tissue homeostasis, tissue repair and regeneration andangiogenesis. This further demonstrates the versatility of the cells ofthe invention for use in the respective therapeutic applications.

In addition, the cells of the invention were further examined withrespect to their safety profile using mouse teratoma formation assay asan indicator. Six SCID mice were used in these experiments. A suspensionof more than 2 million UCMC was injected with a sterile 25G needle intothe thigh muscle of each SCID mouse. Animals were kept up to 6 monthsand tumor formation was assessed. No tumor formation was observed inthese mice (data not shown). This indicates that the cells of theinvention are safe and do not have any capability to form tumors, benignor otherwise.

The UCMC were also analysed for their expression of human leukocyteantigen (HLA) molecules. When testing on major histocompatibilitycomplex (MHC) class I molecules, this analysis showed that HLA-Amolecules were present in high number (test result in arbitrary unit:3201), meaning that the cells are HLA-A positive whereas expression ofHLA-B molecules was insignificant (test result in arbitrary units: 35),meaning the cells are HLA-B negative. These cells also expressed HLA-G(see Example 19). As HLA-B is mainly responsible for rejection reactionin transplantation, this result indicates that the cells of theinvention are not only suitable for autologous transplantation but alsofor allogeneic transplantation. The cells were tested positive for ClassII MHC molecule HLA-DR52 and tested negative for Class II MHC moleculeHLA-DRB4. HLA-DRB1 was also found to be present (0301/05/20/22).

Example 4: Cultivation of Stem/Progenitor Cells in Serum Free Media

UCMC cells were cultured in DMEM containing 10 FCS and in serum-freemedia, PTT-1, PTT-2 and PTT-3. The three media PTT-1, PTT-2 and PTT-3were prepared by one of the present inventors, Dr Phan. In brief, these3 media do not contain fetal bovine or human serum, but containdifferent cytokines and growth factors such as IGF, EGF, TGF-beta,Activin A, BMPs, PDGF, transferrin, and insulin. The growth factorcomponents vary between media to assess differential growthcharacteristics. The cultivation was carried out as follows: Differentproportions of growth factors and cytokines were added in basal media.UCMC were thawed and maintained in these media for 10 days. Cellproliferation was monitored under light microscopy. PTT-2 medium is amixture of M154 a melanocyte culture medium and EpiLife® (CascadeBiologics Inc., Oregon, USA) at ratio of 3:1. Medium 154 is a sterile,liquid tissue culture medium prepared with 200 μM calcium chloride forthe growth of normal human epidermal keratinocytes. Medium 154 is abasal medium containing essential and non-essential amino acids,vitamins, other organic compounds, trace minerals, and inorganic salts.It does not contain antibiotics, antimycotics, hormones, growth factors,or proteins. It is HEPES and bicarbonate buffered and is used in anincubator with an atmosphere of 5% CO₂/95% air.

FIG. 13 shows good UCMC growth in the 4 different media groups (FIG.13-1 to FIG. 13-5), wherein the morphology of UCMC cells is differentdepending on the ratio or proportion of cytokines or growth factorspresent in the respective media. In contrast, bone marrow andadipose-derived mesenchymal cells did not grow well in these serum-freemedia (FIG. 13-6 and FIG. 13-7). Accordingly, the good growth of theUCMC demonstrates the robustness of the cells of the invention and theirhigh viability, indicating that their growth characteristics aresuperior to conventional sources of mesenchymal stem cells as bonemarrow derived and adipose-derived mesenchymal cells. In this respect,it is worth to note that (bovine) serum free medium was used in theseexperiments and that the majority of human mesenchymal cells do not growwell in serum-free medium systems. Thus, using the cells of theinvention in connection with defined serum-free media technologies is abig advantage in cell therapy as the risks of using fetal bovine serumfor cell culture and expansion are removed. (Although use of bovineserum has been practiced for a long time and typically optimizes cellgrowth, concerns of its used have been raised as to the transmission ofzoonoses as Bovine Spongiform Encephalopathy (Mad Cow Disease)).

Example 5: Characterization of the Gene Expression Profile of UmbilicalCord Epithelial and Mesenchymal Stem Cells

The gene expression profile of umbilical cord (amniotic membrane)epithelial and mesenchymal stem cells was analyzed using a DNAmicroarray. For this purpose, UCMC and UCEC were cultured in growthmedia at 37° C., 5% CO₂ until 100% confluence. Cells were synchronizedin basal media for 48 hours then replaced with fresh basal media foranother 48 hours. Total RNA was harvested and sent to Silicon GeneticsMicroarray Service. Data analysis was performed using GeneSpring 7.2).FIG. 14 summarizes the global gene expression. UCEC expressed a total of28055 genes and UCMC expressed a total of 34407 genes. There are 27308overlapping genes expressing in both cell types. 747 genes expressedwere unique to UCEC and 7099 genes expressed were unique to UCMC. Theselected genes of interest are presented in FIG. 14.

Both stem cell types expressed 140 genes related to embryonic stem cellsand embryonic development, further supporting that the cells of theinvention have embryonic stem cell-like properties: Nanog; Alpha-fetalprotein; Pre-B-cell leukemia transcription factor 3; Laminin alpha 5;Carcinoembryonic antigen-like 1; abhydrolase domain containing 2;Delta-like 3 (Drosophila); Muscleblind-like (Drosophila); GNAS complexlocus; Carcinoembryonic antigen-related cell adhesion molecule 3;Palmitoyl-protein thioesterase 2; Pregnancy specific beta-1-glycoprotein2; Carcinoembryonic antigen-like 1; Embryonic ectoderm development;Maternal embryonic leucine zipper kinase; Chorionic somatomammotropinhormone 2; Forkhead box D3; radical fringe homolog (Drosophila); Kinesinfamily member 1B; Myosin, heavy polypeptide 3, skeletal muscle,embryonic; Split hand/foot malformation (ectrodactyly) type 3; TEAdomain family member 3; Laminin, alpha 1; Chorionic somatomammotropinhormone 1; placental lactogen; Corticotropin releasing hormone receptor1; thyrotrophic embryonic factor; Aryl-hydrocarbon receptor nucleartranslocator 2; Membrane frizzled-related protein; Neuregulin1′Collagen, type XVI, alpha 1; Neuregulin 1; Chorionic somatomammotropinhormone 1 (placental lactogen); CUG triplet repeat, RNA binding protein1; Chorionic somatomammotropin hormone 1 (placental lactogen)Bystin-like; MyoD family inhibitor; Retinoic acid induced 2; GNAScomplex locus; Pre-B-cell leukemia transcription factor 4; Laminin,alpha 2 (merosin, congenital muscular dystrophy); SMAD, mothers againstDPP homolog 1 (Drosophila); Homo sapiens transcribed sequence withmoderate similarity to protein pir:D28928 (H. sapiens) D28928pregnancy-specific beta-1 glycoprotein IB, abortive—human (fragment);Kinesin family member 1B; Bruno-like 4, RNA binding protein(Drosophila); Embryo brain specific protein; Pregnancy-induced growthinhibitor; SMAD, mothers against DPP homolog 5 (Drosophila); Chorionicsomatomammotropin hormone 2; Adenylate cyclase activating polypeptide 1(pituitary); Carcinoembryonic antigen-related cell adhesion molecule;Laminin, alpha 3; Protein 0-fucosyltransferase 1; Jagged 1 (Alagillesyndrome); Twisted gastrulation homolog 1 (Drosophila); ELAV (embryoniclethal, abnormal vision, Drosophila)-like 3 (Hu antigen C); Thyrotrophicembryonic factor; Solute carrier family 43, member 3; Inversin;nephronophthisis 2 (infantile); inversion of embryonic turning; Homosapiens inversin (INVS), transcript variant 2, mRNA; Homo sapienstranscribed sequences; Homeo box D8; Embryonal Fyn-associated substrate;ELAV (embryonic lethal, abnormal vision, Drosophila)-like 1 (Hu antigenR); Basic helix-loop-helix domain containing, class B, 2; Oxytocinreceptor; Teratocarcinoma-derived growth factor 1; Fms-related tyrosinekinase 1 (vascular endothelial growth factor/vascular permeabilityfactor receptor); Adrenomedullin; Nuclear receptor coactivator 6-CUGtriplet repeat, RNA binding protein 1; Twisted gastrulation homolog 1(Drosophila); Carcinoembryonic antigen-related cell adhesion molecule 4;Protein tyrosine phosphatase, receptor type, R; Acrg embryonic lethality(mouse) minimal region ortholog; EPH receptor A3; Delta-like 1(Drosophila); Nasal embryonic LHRH factor; Transcription factor CP2-like1; Split hand/foot malformation (ectrodactyly) type 3; Jagged 2; Homosapiens transcribed sequence; Neuregulin 1; Split hand/foot malformation(ectrodactyly) type 1; Solute carrier family 43, member 3;Hydroxyacyl-Coenzyme A dehydrogenase/3-ketoacyl-Coenzyme Athiolase/enoyl-Coenzyme A hydratase (trifunctional protein), alphasubunit; Fucosyltransferase 10 (alpha (1,3) fucosyltransferase); Acrgembryonic lethality (mouse) minimal region ortholog; Carcinoembryonicantigen-related cell adhesion molecule 7; Nucleophosmin/nucleoplasmin,2; Fc fragment of IgG, receptor, transporter, alpha; Twistedgastrulation homolog 1 (Drosophila); Homo sapiens similar to vacuolarprotein sorting 35; maternal-embryonic 3 (LOC146485), mRNA; abhydrolasedomain containing 2; T, brachyury homolog (mouse); A disintegrin andmetalloproteinase domain 10; Ribosomal protein L29; Endothelinconverting enzyme 2; ELAV (embryonic lethal, abnormal vision,Drosophila)-like 1 (Hu antigen R); Trophinin; Homeo box B6; Laminin,alpha 4; Homeo box B6; hypothetical protein FLJ13456; NACHT, leucinerich repeat and PYD containing 5; ELAV (embryonic lethal, abnormalvision, Drosophila)-like 1 (Hu antigen R); Undifferentiated embryoniccell transcription factor 1; Pregnancy-associated plasma protein A,pappalysin 1; Secretoglobin, family 1A, member 1 (uteroglobin);Parathyroid hormone-like hormone; Carcinoembryonic antigen-related celladhesion molecule 1 (biliary glycoprotein); Laminin, alpha 1.

Both stem cell types also expressed thousands of genes related todevelopmental biology, cell growth and differentiation, cellhomeostasis, cell and tissue repair and regeneration. Examples of suchgrowth factors and their receptors is as follows: (G-CSF, FGFs, IGFs,KGF, NGF, VEGFs, PIGF, Angiopoietin, CTGF, PDGFs, HGF, EGF, HDGF,TGF-beta, Activins and Inhibins, Follistatin, BMPs, SCF/c-Kit, LIF,WNTs, SDFs, OncostatinM, Interleukins, Chemokines and many others);MMPs, TIMPs extracellular matrices (collagens, laminins, fibronectins,vitronectins, tenascins, intergrins, syndecans, decorin, fibromoludin,proteoglycans, sparc/osteonectin, mucin, netrin, glypican, cartilageassociated protein, matrilin, hyaluronan, fibulin, ADAMTS, biglycan,discoidin, desmosome components, ICAMs, cadherins, catenins and manyothers); cytokeratins.

There are groups of genes present only in UCMC. These genes are relatedto the following: Normal Physiological Processes (Insulin-like growthfactor 1 (somatomedin C); Insulin-like 4 (placenta); Relaxin 1;Plasminogen; Insulin-like growth factor 1 (somatomedin C); Insulin-like5; Insulin-like growth factor 1 (somatomedin C); Insulin-like growthfactor 2 (somatomedin A), Homeostasis (Radial spokehead-like 1;Hemochromatosis; Chemokine (C-C motif) ligand 5; Interleukin 31 receptorA; Chemokine (C-X-C motif) ligand 12 (stromal cell-derived factor 1);Nuclear receptor subfamily 3, group C, member 2; Hemochromatosis;Chemokine (C-C motif) ligand 23; Chemokine (C-C motif) ligand 23;Ferritin mitochondrial; Peroxisome proliferative activated receptor,gamma, coactivator 1, alpha; Surfactant, pulmonary-associated protein D;Chemokine (C-C motif) ligand 11; Chemokine (C-C motif) ligand 3; Eglnine homolog 2 (C. elegans); Peroxisome proliferative activatedreceptor, gamma, coactivator 1, beta; Chemokine (C-C motif) ligand 1;Chemokine (C-X-C motif) ligand 12 (stromal cell-derived factor 1);ATPase, Na+/K+ transporting, alpha 2 (+) polypeptide; Chemokine (Cmotif) ligand 2; Hemopexin; Ryanodine receptor 3), Morphogenesis(Spectrin, alpha, erythrocytic 1 (elliptocytosis 2); Homeo box D3; Eyesabsent homolog 1 (Drosophila); Ras homolog gene family, member J;Leukocyte specific transcript 1; Ectodysplasin A2 receptor; Glypican 3;Paired box gene 7; Corin, serine protease; Dishevelled, dsh homolog 1(Drosophila); Ras homolog gene family, member J; T-box 3 (ulnar mammarysyndrome); Chondroitin beta1,4 N-acetylgalactosaminyltransferase;Chondroitin beta1,4 N-acetylgalactosaminyltransferase; SRY (sexdetermining region Y)-box 10; Myosin, heavy polypeptide 9, non-muscle;Luteinizing hormone/choriogonadotropin receptor; radical fringe homolog(Drosophila); Secreted frizzled-related protein 5; Wingless-type MMTVintegration site family, member 11; Eyes absent homolog 2 (Drosophila);Muscleblind-like (Drosophila); T-box 5; Mab-21-like 1 (C. elegans);Growth arrest-specific 2; Sex comb on midleg homolog 1 (Drosophila);T-box 6; Filamin-binding LIM protein-1; Melanoma cell adhesion molecule;Twist homolog 1 (acrocephalosyndactyly 3; Saethre-Chotzen syndrome)(Drosophila); Homeo box A11; Keratocan; Fibroblast growth factor 1(acidic); Carboxypeptidase M; CDC42 effector protein (Rho GTPasebinding) 4; LIM homeobox transcription factor 1, beta; Engrailed homolog1; Carboxypeptidase M; Fibroblast growth factor 8 (androgen-induced);Fibroblast growth factor 18; Leukocyte specific transcript 1; Endothelin3; Paired-like homeodomain transcription factor 1), EmbryonicDevelopment (Pregnancy specific beta-1-glycoprotein 3; ELAV (embryoniclethal, abnormal vision, Drosophila)-like 4 (Hu antigen D); Gprotein-coupled receptor 10; Ectodysplasin A2 receptor; ATP-bindingcassette, sub-family B (MDR/TAP), member 4; Pregnancy specificbeta-1-glycoprotein 11; Nasal embryonic LHRH factor; Relaxin 1; Notchhomolog 4 (Drosophila); Pregnancy specific beta-1-glycoprotein 6;pih-2P; Homo sapiens pregnancy-induced hypertension syndrome-relatedprotein (PIH2); Oviductal glycoprotein 1, 120 kDa (mucin 9, oviductin);Progestagen-associated endometrial protein; Myosin, light polypeptide 4,alkali; atrial, embryonic; Prolactin; Notch homolog 4 (Drosophila);Pre-B-cell leukemia transcription factor 1; radical fringe homolog(Drosophila); Corticotropin releasing hormone; Nuclear receptorsubfamily 3, group C, member 2; Neuregulin 2; Muscleblind-like(Drosophila); Myosin, light polypeptide 4, alkali; atrial, embryonic;Homo sapiens cDNA FLJ27401 fis, clone WMC03071; Extraembryonic,spermatogenesis, homeobox 1-like; Insulin-like 4 (placenta); Humanprocessed pseudo-pregnancy-specific glycoprotein (PSG12) gene, exon B2Ccontaining 3′ untranslated regions of 2 alternative splice sites C1 andC2; Fms-related tyrosine kinase 1 (vascular endothelial growthfactor/vascular permeability factor receptor); Pre-B-cell leukemiatranscription factor 1; Pregnancy specific beta-1-glycoprotein 3;carcinoembryonic antigen-related cell adhesion molecule 1 (biliaryglycoprotein); Steroid sulfatase (microsomal), arylsulfatase C, isozymeS; Homeo box B6; Protein 0-fucosyltransferase 1; LIM homeoboxtranscription factor 1, beta; Carcinoembryonic antigen-related celladhesion molecule 1 (biliary glycoprotein); Follicle stimulatinghormone, beta polypeptide; Angiotensinogen (serine (or cysteine)proteinase inhibitor, clade A (alpha-1 antiproteinase, antitrypsin),member 8); Carcinoembryonic antigen-related cell adhesion molecule 6(non-specific cross reacting antigen); Protein kinase C, alpha bindingprotein; Collectin sub-family member 10 (C-type lectin); Laminin, alpha1), the Extracellular Space (Carboxylesterase 1 (monocyte/macrophageserine esterase 1); Fibroblast growth factor 5; Progastricsin(pepsinogen C); Sperm associated antigen 11; Proprotein convertasesubtilisin/kexin type 2; Hyaluronan binding protein 2; Sema domain,immunoglobulin domain (Ig), short basic domain, secreted, (semaphorin)3F; Interleukin 2; Chymotrypsin-like; Norrie disease (pseudoglioma);mucin 5, subtypes A and C, tracheobronchial/gastric; Carboxypeptidase B2(plasma, carboxypeptidase U); radical fringe homolog (Drosophila);Pregnancy specific beta-1-glycoprotein 11; Meprin A, alpha (PABA peptidehydrolase); Tachykinin, precursor 1 (substance K, substance P,neurokinin 1, neurokinin 2, neuromedin L, neurokinin alpha, neuropeptideK, neuropeptide gamma); Fibroblast growth factor 8 (androgen-induced);Fibroblast growth factor 13; Hemopexin; Breast cancer 2, early onset;Fibroblast growth factor 14; Retinoschisis (X-linked, juvenile) 1;Chitinase 3-like 1 (cartilage glycoprotein-39); Dystonin; Secretoglobin,family 1 D, member 2; Noggin; WAP four-disulfide core domain 2; CD5antigen-like (scavenger receptor cysteine rich family); Scrapieresponsive protein 1; Gremlin 1 homolog, cysteine knot superfamily(Xenopus laevis); Interleukin 16 (lymphocyte chemoattractant factor);Chemokine (C-C motif) ligand 26; Nucleobindin 1; Fibroblast growthfactor 18; Insulin-like growth factor binding protein 1; Surfactant,pulmonary-associated protein A1; Delta-like 1 homolog (Drosophila);Cocaine- and amphetamine-regulated transcript; Meprin A, beta;Interleukin 17F; Complement factor H; Cysteine-rich secretory protein 2;Dystonin; WAP four-disulfide core domain 1; Prolactin; Surfactant,pulmonary-associated protein B; Fibroblast growth factor 5; Dickkopfhomolog 2 (Xenopus laevis); Sperm associated antigen 11; Chemokine (C-Cmotif) ligand 11; Meprin A, alpha (PABA peptide hydrolase); Chitinase3-like 2; C-fos induced growth factor (vascular endothelial growthfactor D); Chemokine (C-C motif) ligand 4; Poliovirus receptor;Hyaluronoglucosaminidase 1; Oviductal glycoprotein 1, 120 kDa (mucin 9,oviductin); Chemokine (C-X-C motif) ligand 9; Secreted frizzled-relatedprotein 5; Amelogenin (amelogenesis imperfecta 1, X-linked); Relaxin 1;Sparc/osteonectin, cwcv and kazal-like domains proteoglycan (testican);Chemokine (C-C motif) ligand 26; Fibroblast growth factor 1 (acidic);Angiopoietin-like 2; Fms-related tyrosine kinase 1 (vascular endothelialgrowth factor/vascular permeability factor receptor); Dystonin;Insulin-like 4 (placenta); Transcobalamin II; macrocytic anemia;Chemokine (C-C motif) ligand 1; Insulin-like growth factor bindingprotein, acid labile subunit; Complement factor H; Pregnancy specificbeta-1-glycoprotein 6; Silver homolog (mouse); Proteoglycan 4;Fibroblast growth factor 16; Cytokine-like protein C17; Granulysin;Angiopoietin 2; Chromogranin B (secretogranin 1); Sema domain,immunoglobulin domain (Ig), and GPI membrane anchor, (semaphorin) 7A;Pleiotrophin (heparin binding growth factor 8, neurite growth-promotingfactor 1); Chloride channel, calcium activated, family member 3;Secretoglobin, family 1 D, member 1; Fibulin 1; Phospholipase A2receptor 1, 180 kDa), and the Extracellular Matrix (ADAMTS-like 1;Periostin, osteoblast specific factor; Glypican 5; Leucine rich repeatneuronal 3; Transglutaminase 2 (C polypeptide,protein-glutamine-gamma-glutamyltransferase); A disintegrin-like andmetalloprotease (reprolysin type) with thrombospondin type 1 motif, 2;Microfibrillar-associated protein 4; Glypican 3; Collagen, type V, alpha3; Tissue inhibitor of metalloproteinase 2; Keratocan; Cartilageoligomeric matrix protein; Lumican; Hyaluronan and proteoglycan linkprotein 3; Statherin; A disintegrin-like and metalloprotease (reprolysintype) with thrombospondin type 1 motif, 3; Spondin 1, extracellularmatrix protein; Chitinase 3-like (cartilage glycoprotein-39); Collagen,type IV, alpha 3 (Goodpasture antigen); Wingless-type MMTV integrationsite family, member 7B; Collagen, type VI, alpha 2; Lipocalin 7;Hyaluronan and proteoglycan link protein 4; A disintegrin-like andmetalloprotease (reprolysin type) with thrombospondin type 1 motif, 5(aggrecanase-2); Fibronectin 1; Matrilin 1, cartilage matrix protein;Hypothetical protein FLJ13710; Chondroitin beta1,4N-acetylgalactosaminyltransferase; Matrix metalloproteinase 16(membrane-inserted); Von Willebrand factor; Collagen, type VI, alpha 2;Transmembrane protease, serine 6; Matrix metalloproteinase 23B; Matrixmetalloproteinase 14 (membrane-inserted); Leucine rich repeat neuronal3; SPARC-like (mast9, hevin); Sparc/osteonectin, cwcv and kazal-likedomains proteoglycan (testican) 3; Dermatopontin; collagen, type XIV,alpha 1 (undulin); Amelogenin, Y-linked; Nidogen (enactin); ADAMTS-like2; Hyaluronan and proteoglycan link protein 2; Collagen, type XV, alpha1; Glypican 6; Matrix metalloproteinase 12 (macrophage elastase);Amelogenin (amelogenesis imperfecta 1, X-linked); A disintegrin-like andmetalloprotease (reprolysin type) with thrombospondin type 1 motif, 15;Transmembrane protease, serine 6; A disintegrin-like and metalloprotease(reprolysin type) with thrombospondin type 1 motif, 16;Sparc/osteonectin, cwcv and kazal-like domains proteoglycan (testican);A disintegrin-like and metalloprotease (reprolysin type) withthrombospondin type 1 motif, 20; Collagen, type XI, alpha 1; Hyaluronanand proteoglycan link protein 1; Chondroitin beta1,4N-acetylgalactosaminyltransferase; Asporin (LRR class 1); Collagen, typeIII, alpha 1 (Ehlers-Danlos syndrome type IV, autosomal dominant);Secreted phosphoprotein 1 (osteopontin, bone sialoprotein I, earlyT-lymphocyte activation 1); Matrix Gla protein; Fibulin 5; collagen,type XIV, alpha (undulin); Tissue inhibitor of metalloproteinase 3(Sorsby fundus dystrophy, pseudoinflammatory); Collagen, type XXV, alpha1; Cartilage oligomeric matrix protein; Collagen, type VI, alpha 1;Chondroadherin; Collagen, type XV, alpha 1; A disintegrin-like andmetalloprotease (reprolysin type) with thrombospondin type 1 motif, 16;Collagen, type IV, alpha 4; Dentin matrix acidic phosphoprotein;Collagen, type IV, alpha 1; Thrombospondin repeat containing 1; Matrixmetalloproteinase 16 (membrane-inserted); Collagen, type I, alpha 2;Fibulin 1; Tectorin beta; Glycosylphosphatidylinositol specificphospholipase D1; Upregulated in colorectal cancer gene 1).Cytoskeleton: (Filamin B, beta (actin binding protein 278); Centrin,EF-hand protein, 1; FERM domain containing 3; Bridging integrator 3;Parvin, gamma; Rho guanine nucleotide exchange factor (GEF) 11; Tyrosinekinase 2; Kelch-like 4 (Drosophila); Spectrin, beta, erythrocytic(includes spherocytosis, clinical type I); Arg/Abl-interacting proteinArgBP2; Advillin; Spectrin repeat containing, nuclear envelope 1;Catenin (cadherin-associated protein), delta 1; Erythrocyte membraneprotein band 4.1 like 5; Catenin (cadherin-associated protein), alpha 2;Chemokine (C-C motif) ligand 3; Sarcoglycan, gamma (35 kDadystrophin-associated glycoprotein); Nebulin; Thymosin, beta, identifiedin neuroblastoma cells; 3-phosphoinositide dependent protein kinase-1;Wiskott-Aldrich syndrome protein interacting protein; Dystonin;Huntingtin interacting protein 1; KIAA0316 gene product; Tropomodulin 4(muscle); Deleted in liver cancer 1; Villin-like; Syntrophin, beta 1(dystrophin-associated protein A1, 59 kDa, basic component 1); Proteinkinase, cGMP-dependent, type I; Homo sapiens similar to keratin 8;cytokeratin 8; keratin, type II cytoskeletal 8 (LOC345751), mRNA;Adducin 1 (alpha); Protein kinase C and casein kinase substrate inneurons 3; Dystonin; Kell blood group; Filamin A interacting protein 1;Growth arrest-specific 2; Chromosome 1 open reading frame 1;Stathmin-like 2; Spectrin, alpha, erythrocytic 1 (elliptocytosis 2);FKSG44 gene; Kinesin family member 1C; Tensin; Kaptin (actin bindingprotein); Neurofibromin 2 (bilateral acoustic neuroma); Pleckstrinhomology, Sec7 and coiled-coil domains 2 (cytohesin-2); Actin-relatedprotein Tl; Wiskott-Aldrich syndrome-like; Kelch-like 4 (Drosophila);Fascin homolog 1, actin-bundling protein (Strongylocentrotuspurpuratus); Amphiphysin (Stiff-Man syndrome with breast cancer 128 kDaautoantigen); Polycystic kidney disease 2-like 1; Ankyrin 2, neuronal;CDC42 binding protein kinase alpha (DMPK-like); Hypothetical proteinFLJ36144; Arg/Abl-interacting protein ArgBP2; Formin-like 3; Catenin(cadherin-associated protein), beta 1, 88 kDa; Profilin 2; Synaptopodin2-like; Syntrophin, gamma 2; Phospholipase D2; Engulfment and cellmotility 2 (ced-12 homolog, C. elegans); Neurofilament, lightpolypeptide 68 kDa; Dystonin; Actin-like 7B; Kinesin family member 1C;PDZ and LIM domain 3; Adducin 2 (beta); obscurin, cytoskeletalcalmodulin and titin-interacting RhoGEF; Tubulin, beta polypeptideparalog; Filamin A interacting protein 1; Talin 1; Homo sapiens similarto [Segment 1 of 2] Piccolo protein (Aczonin) (LOC375597); CDC42effector protein (Rho GTPase binding) 4; Syndecan 1; Filamin A, alpha(actin binding protein 280); Profilin 2; Tensin like Cl domaincontaining phosphatase; Hypothetical protein MGC33407; Rho family GTPase1; Flavoprotein oxidoreductase MICAL2; Ca2+-dependent secretionactivator; Rabphilin 3A-like (without C2 domains); Myosin XVA; Proteinkinase, cGMP-dependent, type I; Myosin regulatory light chaininteracting protein; Kinesin family member 13B; Muscle RAS oncogenehomolog; Spectrin, beta, non-erythrocytic 1; TAO kinase 2; Filamin B,beta (actin binding protein 278); Neurofibromin 2 (bilateral acousticneuroma); Catenin (cadherin-associated protein), alpha 3; obscurin,cytoskeletal calmodulin and titin-interacting RhoGEF; Coronin, actinbinding protein, 1A; Erythrocyte membrane protein band 4.1-like 1;Spectrin, beta, non-erythrocytic 4; Thymosin, beta 4, Y-linked; Tektin 2(testicular); Ras homolog gene family, member J; Serine/threonine kinasewith Dbl- and pleckstrin homology domains; Dystrobrevin, beta; Actin,gamma 2, smooth muscle, enteric; Tara-like protein; Caspase 8,apoptosis-related cysteine protease; Kelch repeat and BTB (POZ) domaincontaining 10; Mucin 1, transmembrane; Microtubule-associated proteintau; Tensin; Ras homolog gene family, member F (in filopodia); Adducin 1(alpha); Actinin, alpha 4; Erythrocyte membrane protein band 4.1(elliptocytosis 1, RH-linked); Bicaudal D homolog 2 (Drosophila);Ankyrin 3, node of Ranvier (ankyrin G); Myosin VIIA (Usher syndrome 1B(autosomal recessive, severe)); Catenin (cadherin-associated protein),alpha 2; Homo sapiens similar to keratin 8, type II cytoskeletal—human(LOC285233); Fascin homolog 3, actin-bundling protein, testicular; Rashomolog gene family, member J; Beaded filament structural protein 2,phakinin; Desmin; Myosin X; Signal-induced proliferation-associated gene1; Scinderin; Coactosin-like 1 (Dictyostelium); Engulfment and cellmotility 2 (ced-12 homolog, C. elegans); Tubulin, beta 4; Ca²⁺-dependentsecretion activator; FERM domain containing 4A; Actin, alpha 1, skeletalmuscle; Talin 1; Caldesmon 1; Filamin-binding LIM protein-1;Microtubule-associated protein tau; Syntrophin, alpha 1(dystrophin-associated protein A1, 59 kDa, acidic component); Adducin 2(beta); Filamin A interacting protein 1; PDZ and LIM domain 3;Erythrocyte membrane protein band 4.1 like 4B; FYN binding protein(FYB-120/130); Bridging integrator 3). Extracellular: (Adisintegrin-like and metalloprotease (reprolysin type) withthrombospondin type 1 motif, 20; SPARC-like 1 (mast9, hevin); Serine (orcysteine) proteinase inhibitor, clade G (C1 inhibitor), member 1,(angioedema, hereditary); Urocortin; Chymotrypsin-like; Platelet-derivedgrowth factor beta polypeptide (simian sarcoma viral (v-sis) oncogenehomolog); BMP-binding endothelial regulator precursor protein;Complement factor H; Chorionic somatomammotropin hormone-like 1;Chemokine (C-C motif) ligand 18 (pulmonary and activation-regulated);Fibronectin 1; Pregnancy specific beta-1-glycoprotein 3; Adisintegrin-like and metalloprotease (reprolysin type) withthrombospondin type 1 motif, 3; CocoaCrisp; Insulin-like 4 (placenta);Wingless-type MMTV integration site family, member 11; Cartilageoligomeric matrix protein; Transmembrane protease, serine 6; C-fosinduced growth factor (vascular endothelial growth factor D); Familywith sequence similarity 12, member B (epididymal); Protein phosphatase1, regulatory subunit 9B, spinophilin; Transcobalamin II; macrocyticanemia; Coagulation factor V (proaccelerin, labile factor);Phospholipase A2, group IID; Tumor necrosis factor, alpha-inducedprotein 6; Collagen, type XV, alpha 1; Hyaluronan and proteoglycan linkprotein 3; collagen, type XIV, alpha 1 (undulin); Interleukin 19;Protease inhibitor 15; Cholinergic receptor, nicotinic, beta polypeptide1 (muscle); Lysyl oxidase-like 3; Insulin-like growth factor bindingprotein 5; Growth hormone 1; Casein beta; NEL-like 2 (chicken); I factor(complement); Chemokine (C-C motif) ligand 23; Interferon, alpha 2;Matrix metalloproteinase 16 (membrane-inserted); Matrixmetalloproteinase 12 (macrophage elastase); Glypican 5; Pregnancyspecific beta-1-glycoprotein 3; Fibroblast growth factor 6; Gremlin 1homolog, cysteine knot superfamily (Xenopus laevis); Protein S (alpha);Chondroitin beta1,4 N-acetylgalactosaminyltransferase;Glycosylphosphatidylinositol specific phospholipase D1; Fibroblastgrowth factor 1 (acidic); Spondin 1, extracellular matrix protein; Bonemorphogenetic protein 1; Surfactant, pulmonary-associated protein B;Dentin matrix acidic phosphoprotein; Lipoprotein, Lp(a); Mucin 1,transmembrane; Mannan-binding lectin serine protease 1 (C4/C2 activatingcomponent of Ra-reactive factor); Meprin A, beta; Secretoglobin, family1D, member 1; Asporin (LRR class 1); Chemokine (C-C motif) ligand 25;Cytokine-like protein C17; Insulin-like 5; Meprin A, alpha (PABA peptidehydrolase); Scrapie responsive protein 1; Fibroblast growth factor 18;Chemokine (C-X-C motif) ligand 9; Inhibin, beta B (activin AB betapolypeptide); Fibroblast growth factor 8 (androgen-induced); Granulysin;Cocaine- and amphetamine-regulated transcript; Collagen, type I, alpha2; Chemokine (C-C motif) ligand 17; Chemokine (C-C motif) ligand 23;Sparc/osteonectin, cwcv and kazal-like domains proteoglycan (testican)3; Gamma-aminobutyric acid (GABA) A receptor, beta 3; Defensin, alpha 4,corticostatin; Leucine rich repeat neuronal 3; Glypican 6;Mitogen-activated protein kinase kinase 2; Coagulation factor XI (plasmathromboplastin antecedent); Chemokine (C-C motif) ligand 5; Dystonin;Frizzled-related protein; Coagulation factor XIII, A1 polypeptide;Insulin-like growth factor 1 (somatomedin C); Hypothetical proteinMGC45438; Sperm associated antigen 11; Insulin-like growth factor 1(somatomedin C); Periostin, osteoblast specific factor;Alpha-2-macroglobulin; Gamma-aminobutyric acid (GABA) A receptor, alpha5; Serine (or cysteine) proteinase inhibitor, clade A (alpha-1antiproteinase, antitrypsin), member 3; Silver homolog (mouse);Frizzled-related protein; Chondroadherin; Chondroitin beta1,4N-acetylgalactosaminyltransferase; 5-hydroxytryptamine (serotonin)receptor 3, family member C; Collagen, type VI, alpha 2; Toll-likereceptor 9; Amelogenin, Y-linked; Vascular endothelial growth factor B;Radial spokehead-like 1; Fms-related tyrosine kinase 1 (vascularendothelial growth factor/vascular permeability factor receptor);Protease inhibitor 16; Interleukin 2; Clusterin (complement lysisinhibitor, SP-40,40, sulfated glycoprotein 2, testosterone-repressedprostate message 2, apolipoprotein J); Follicle stimulating hormone,beta polypeptide; A disintegrin-like and metalloprotease (reprolysintype) with thrombospondin type 1 motif, 16; Lysozyme (renalamyloidosis); radical fringe homolog (Drosophila); Insulin-like growthfactor binding protein 5; Taxilin; Apolipoprotein A-V; Platelet derivedgrowth factor C; Chemokine (C-C motif) ligand 3-like 1; Fibroblastgrowth factor 16; Collagen, type VI, alpha 2; Serine (or cysteine)proteinase inhibitor, clade C (antithrombin), member 1; Chemokine (C-Cmotif) ligand 11; Collagen, type IV, alpha 4; Bruton agammaglobulinemiatyrosine kinase; Insulin-like growth factor 2 (somatomedin A);Kazal-type serine protease inhibitor domain 1; Fibrinogen, A alphapolypeptide; Chemokine (C-C motif) ligand 1; Inhibin, beta E; Sexhormone-binding globulin; Collagen, type IV, alpha 1;Lecithin-cholesterol acyltransferase; Cysteine-rich secretory protein 2;Hyaluronan and proteoglycan link protein 1; Natriuretic peptideprecursor C; Ribonuclease, RNase A family, k6; Fibroblast growth factor14; ADAMTS-like 2; Collagen, type IV, alpha 3 (Goodpasture antigen);Angiopoietin 2; Apolipoprotein L, 3; Chemokine (C-X-C motif) ligand 12(stromal cell-derived factor 1); Hyaluronan binding protein 2;Coagulation factor VII (serum prothrombin conversion accelerator);collagen, type XIV, alpha 1 (undulin); Oviductal glycoprotein 1, 120 kDa(mucin 9, oviductin); Matrilin 1, cartilage matrix protein; mucin 5,subtypes A and C, tracheobronchial/gastric; Tumor necrosis factorreceptor superfamily, member 11 b (osteoprotegerin); Transglutaminase 2(C polypeptide, protein-glutamine-gamma-glutamyltransferase); Keratocan;Collagen, type V, alpha 3; WAP four-disulfide core domain 2; Chemokine(C-X3-C motif) ligand 1; Serine (or cysteine) proteinase inhibitor,clade D (heparin cofactor), member 1; Secretory protein LOC348174;Coagulation factor X; Interleukin 16 (lymphocyte chemoattractantfactor); Pancreatic lipase-related protein 2; HtrA serine peptidase 3;Glycine receptor, alpha 3; CD5 antigen-like (scavenger receptor cysteinerich family); Hypothetical protein MGC39497; Coagulation factor VIII,procoagulant component (hemophilia A); Dermatopontin; Noggin; SecretedLY6/PLAUR domain containing 1; ADAMTS-like 1; Alpha-1-B glycoprotein;Chromosome 20 open reading frame 175; Wingless-type MMTV integrationsite family, member 8B; Fibulin 1; Fibulin 5; Cathepsin S; Nidogen(enactin); Chemokine (C-C motif) ligand 26; Endothelial cell-specificmolecule 1; Chitinase 3-like 1 (cartilage glycoprotein-39);Gamma-aminobutyric acid (GABA) A receptor, beta 1; Secretoglobin, family1 D, member 2; Mannan-binding lectin serine protease 1 (C4/C2 activatingcomponent of Ra-reactive factor); ADAMTS-like 1; Sema domain,immunoglobulin domain (Ig), and GPI membrane anchor, (semaphorin) 7A; Adisintegrin-like and metalloprotease (reprolysin type) withthrombospondin type 1 motif, 15; Proprotein convertase subtilisin/kexintype 2; Insulin-like growth factor 1 (somatomedin C); Retinoschisis(X-linked, juvenile) 1; A disintegrin-like and metalloprotease(reprolysin type) with thrombospondin type 1 motif, 16; Chemokine (Cmotif) ligand 2; Fibroblast growth factor 5; Sperm associated antigen11; Microfibrillar-associated protein 4; Poliovirus receptor;Extracellular signal-regulated kinase 8; Transmembrane protease, serine6; Protein kinase C, alpha; Chitinase 3-like 2; Interleukin 9;Apolipoprotein L, 6; Surfactant, pulmonary-associated protein A1;Collagen, type VI, alpha 1; Apolipoprotein L, 6; Hypothetical proteinFLJ13710; Carboxypeptidase B2 (plasma, carboxypeptidase U);Bactericidal/permeability-increasing protein-like 2; Fibroblast growthfactor 5; Secreted phosphoprotein 1 (osteopontin, bone sialoprotein I,early T-lymphocyte activation 1); HtrA serine peptidase 3; Deleted inliver cancer 1; Endothelial cell-specific molecule 1; Von Willebrandfactor; A disintegrin-like and metalloprotease (reprolysin type) withthrombospondin type 1 motif, 5 (aggrecanase-2); Sema domain,immunoglobulin domain (Ig), short basic domain, secreted, (semaphorin)3A; Chemokine (C-X-C motif) ligand 12 (stromal cell-derived factor 1);Statherin; Extracellular signal-regulated kinase 8; Tissue inhibitor ofmetalloproteinase 3 (Sorsby fundus dystrophy, pseudoinflammatory);Platelet factor 4 (chemokine (C-X-C motif) ligand 4); Surfactant,pulmonary-associated protein D; Complement factor H; Delta-like 1homolog (Drosophila); WAP four-disulfide core domain 1; Insulin-likegrowth factor binding protein, acid labile subunit; Breast cancer 2,early onset; Pre-B lymphocyte gene 1; Corticotropin releasing hormone;Hypothetical protein DKFZp434B044; Prolactin-induced protein; RAS guanylreleasing protein 4; Progastricsin (pepsinogen C); Sema domain,immunoglobulin domain (Ig), short basic domain, secreted, (semaphorin)3F; Upregulated in colorectal cancer gene 1; Proteoglycan 4; Cholinergicreceptor, nicotinic, delta polypeptide; Cartilage oligomeric matrixprotein; ABO blood group (transferase A, alpha1-3-N-acetylgalactosaminyltransferase; transferase B, alpha1-3-galactosyltransferase); Interleukin 12A (natural killer cellstimulatory factor 1, cytotoxic lymphocyte maturation factor 1, p35);Fibroblast growth factor 7 (keratinocyte growth factor); Kin of IRRElike 3 (Drosophila); Cholinergic receptor, nicotinic, alpha polypeptide2 (neuronal); Palate, lung and nasal epithelium carcinoma associated;Collagen, type XV, alpha 1; Pleiotrophin (heparin binding growth factor8, neurite growth-promoting factor 1); Angiopoietin-like 2; Norriedisease (pseudoglioma); Chemokine (C-C motif) ligand 3; Chitinase 3-like1 (cartilage glycoprotein-39); Inter-alpha (globulin) inhibitor H3;Amelogenin (amelogenesis imperfecta 1, X-linked); Epidermal growthfactor (beta-urogastrone); Fibroblast growth factor 13; Wingless-typeMMTV integration site family, member 7B; Cholinergic receptor,nicotinic, gamma polypeptide; Pregnancy specific beta-1-glycoprotein 6;Matrix metalloproteinase 14 (membrane-inserted); Chemokine (C-C motif)ligand 26; Interferon, alpha 6; Tachykinin, precursor 1 (substance K,substance P, neurokinin 1, neurokinin 2, neuromedin L, neurokinin alpha,neuropeptide K, neuropeptide gamma); Secreted frizzled-related protein5; Hyaluronan and proteoglycan link protein 4; Complement component 4B;Matrix metalloproteinase 16 (membrane-inserted); Fibroblast growthfactor 7 (keratinocyte growth factor); Apolipoprotein C-II; Chloridechannel, calcium activated, family member 3; Tetranectin (plasminogenbinding protein); Collagen, type III, alpha 1 (Ehlers-Danlos syndrometype IV, autosomal dominant); KIAA0556 protein; Chemokine (C-C motif)ligand 4; Hemopexin; Inter-alpha (globulin) inhibitor H1; Relaxin 1;Matrix Gla protein; A disintegrin-like and metalloprotease (reprolysintype) with thrombospondin type 1 motif, 2; Interferon (alpha, beta andomega) receptor 2; Acid phosphatase, prostate; Guanine nucleotidebinding protein (G protein), gamma 8; Matrix metalloproteinase 23B;Meprin A, alpha (PABA peptide hydrolase); Hyaluronoglucosaminidase 1;Angiotensinogen (serine (or cysteine) proteinase inhibitor, clade A(alpha-1 antiproteinase, antitrypsin), member 8); Cartilage intermediatelayer protein, nucleotide pyrophosphohydrolase; Purinergic receptor P2X,ligand-gated ion channel, 7; Glypican 3; Tectorin beta; Interferon,alpha 5; Lipocalin 7; Platelet factor 4 variant 1; Nucleobindin 1;Collagen, type XI, alpha 1; Gastric inhibitory polypeptide;Thrombospondin repeat containing 1; 5-hydroxytryptamine (serotonin)receptor 3 family member D; Collagen, type XXV, alpha 1; Growthdifferentiation factor 9; Hypothetical protein DKFZp434B044; Endothelin3; Chemokine (C motif) ligand 2; Prokineticin 2; Tumor necrosis factorreceptor superfamily, member 11b (osteoprotegerin); Tissue inhibitor ofmetalloproteinase 2; Dystonin; Chromogranin B (secretogranin 1);Hyaluronan and proteoglycan link protein 2; Leucine rich repeat neuronal3; Lumican; Matrilin 1, cartilage matrix protein; Phospholipase A2,group IIA (platelets, synovial fluid); Carboxylesterase 1(monocyte/macrophage serine esterase 1); Sparc/osteonectin, cwcv andkazal-like domains proteoglycan (testican); Dickkopf homolog 2 (Xenopuslaevis); Gamma-aminobutyric acid (GABA) A receptor, alpha 3; Pregnancyspecific beta-1-glycoprotein 11; Insulin-like growth factor bindingprotein 1; Defensin, beta 106; Interleukin 17F; Ligand-gated ion channelsubunit; Phospholipase A2 receptor 1, 180 kDa; I factor (complement);Dystonin; LAG1 longevity assurance homolog 1 (S. cerevisiae); Prolactin;Testis expressed sequence 264; Sema domain, immunoglobulin domain (Ig),short basic domain, secreted, (semaphorin) 3D; secreted frizzled-relatedprotein 2; secreted frizzled-related protein 4).

There are groups of genes present only in UCEC. These genes are relatedto the following: Homeostasis (Albumin; Calcium-sensing receptor;Aquaporin 9; Lactotransferrin. Morphogenesis: Homeo box HB9; EpithelialV-like antigen 1). Embryonic Development (Relaxin 2; Carcinoembryonicantigen-related cell adhesion molecule 8; Indoleamine-pyrrole 2,3dioxygenase; EPH receptor A3; Thyrotrophic embryonic factor; Pregnancyspecific beta-1-glycoprotein 1; Laminin, alpha 3), the ExtracellularSpace (Surfactant, pulmonary-associated protein A1; Pregnancy specificbeta-1-glycoprotein 1; Lactotransferrin; TGF-alpha; Albumin; FGF-23;S100 calcium binding protein A9 (calgranulin B)), the ExtracellularMatrix (Laminin, beta 4; Laminin, alpha 3; Zona pellucida glycoprotein4. Structural Molecule Activity: Chromosome 21 open reading frame 29;Laminin, alpha 3; Microtubule-associated protein 2; Laminin, beta 4;Keratin 6B; Ladinin 1; Keratin 6A; Occludin; Loricrin; Erythrocytemembrane protein band 4.1 (elliptocytosis 1, RH-linked); Crystallin,beta A2; eye lens structural protein; Contactin associated protein-like4; Claudin 19; Hypothetical protein LOC144501; Keratin 6E; Keratin 6L;Lens intrinsic membrane protein 2, 19 kDa), the Cytoskeleton(Microtubule-associated protein 2; Erythrocyte membrane protein band 4.1like 5; Homo sapiens trichohyalin (THH); Keratin 6B; Keratin 6A;Epithelial V-like antigen 1; Hook homolog 1 (Drosophila); Loricrin;Erythrocyte membrane protein band 4.1 (elliptocytosis 1, RH-linked);Tropomodulin 1; MAP/microtubule affinity-regulating kinase 1; Keratin6E; Actin binding LIM protein family, member 2), Cell Adhesion Molecules(Cadherin 19, type 2; Myeloid/lymphoid or mixed-lineage leukemia;Chromosome 21 open reading frame 29; Kin of IRRE like 2; Laminin, alpha3; Sialoadhesin; CD84 antigen (leukocyte antigen); Lectin,galactoside-binding, soluble, 2 (galectin 2); Epithelial V-like antigen1; CD96 antigen; Tubulointerstitial nephritis antigen; Carcinoembryonicantigen-related cell adhesion molecule 8; IL-18; Immunoglobulinsuperfamily, member 1; Integrin, beta 8; Ornithine arbamoyltransferase;Integrin, beta 6; Contactin associated protein-like 4; Collagen, typeXVII, alpha 1; Cadherin-like 26; Mucin and cadherin-like), CellDifferentiation proteins (Protein tyrosine phosphatase, receptor-type, Zpolypeptide 1; Laminin, alpha 3; CD84 antigen (leukocyte antigen);EDRF2; Homo sapiens erythroid differentiation-related factor 2; Tumorprotein p73-like; NB4 apoptosis/differentiation related protein; Homosapiens PNAS-133; Similar to seven in absentia 2; Interleukin 24;Keratin 6B; Keratin 6A; Dehydrogenase/reductase (SDR family) member 9;Gap junction protein, beta 5 (connexin 31.1); Iroquois homeobox protein4; Ventral anterior homeobox 2; Chemokine (C-X-C motif) ligand 10; Tumornecrosis factor receptor superfamily, member 17; Calcium channel,voltage-dependent, beta 2 subunit; Parkinson disease (autosomalrecessive, juvenile) 2, parkin; Kallikrein 7 (chymotryptic, stratumcorneum); Glial cells missing homolog 2; AP-2 alpha; Protein tyrosinephosphatase, receptor-type, Z polypeptide 1; Troponin T1; Sciellin;Glucosaminyl (N-acetyl) transferase 2, !-branching enzyme; Collagen,type XVII, alpha 1; Suppressor of cytokine signaling 2; Distal-lesshomeo box 1; Zygote arrest 1; Interleukin 20; Growth differentiationfactor 3; FGF-23; Wingless-type MMTV integration site family, member 8A.Extracellular: Chromosome 21 open reading frame 29; Laminin, alpha 3;Laminin, beta 4; Interleukin 24; Pregnancy specific beta-1-glycoprotein1; Chemokine (C-X-C motif) ligand 11; Surfactant, pulmonary-associatedprotein A1; Prepronociceptin; 5-hydroxytryptamine (serotonin) receptor3B; Carcinoembryonic antigen-related cell adhesion molecule 8; Chemokine(C-X-C motif) ligand 10; IL-18 (interferon-gamma-inducing factor);Lactotransferrin; Albumin; Fas ligand (TNF superfamily, member 6);Cholinergic receptor, nicotinic, beta polypeptide 4; Cathelicidinantimicrobial peptide; Airway trypsin-like protease; S100 calciumbinding protein A9 (calgranulin B); TGF-alpha; Kallikrein 10; Serineprotease inhibitor, Kunitz type 1; WNT1 inducible signaling pathwayprotein 3; Relaxin 2; Interferon, kappa; Defensin, beta 103A; IL-20;Zona pellucida glycoprotein 4; Growth differentiation factor 3; FGF-23;Wingless-type MMTV integration site family, member 8A; Complement factorH-related 5), Developmental proteins (EPH receptor A3; NIMA (never inmitosis gene a)-related kinase 2; Zinc finger protein 282; TANK-bindingkinase 1; MRE11 meiotic recombination 11 homolog A; E2F transcriptionfactor 2; Protein tyrosine phosphatase, receptor-type, Z polypeptide 1;Homo sapiens clone 161455 breast expressed mRNA from chromosome X;Laminin, alpha 3; v-myb myeloblastosis viral oncogene homolog(avian)-like 1; Regulator of G-protein signalling 11;Microtubule-associated protein 2; Transmembrane protein 16A;Adenomatosis polyposis coli 2; Homeo box HB9; Centromere protein F,350/400ka (mitosin); CD84 antigen (leukocyte antigen); EDRF2; Homosapiens erythroid differentiation-related factor 2; Tumor proteinp73-like; NB4 apoptosis/differentiation related protein; Homo sapiensPNAS-133; Forkhead box P2; Homo sapiens gastric-associateddifferentially-expressed protein YA61P (YA61); Tenascin N; Chromosome 6open reading frame 49; Zinc finger protein 462; Zinc finger protein 71(Cos26); SRY (sex determining region Y)-box 7; Triggering receptorexpressed on myeloid cells-like 4; Interleukin 24; Pregnancy specificbeta-1-glycoprotein 1; Chondroitin sulfate proteoglycan 5 (neuroglycanC); Keratin 6B; Keratin 6A; Dehydrogenase/reductase (SDR family) member9; Epithelial V-like antigen 1; Gap junction protein, beta 5 (connexin31.1); G protein-coupled receptor 51; Interferon regulatory factor 6;Neurotrophin 5 (neurotrophin 4/5); CD96 antigen; Iroquois homeoboxprotein 4; Interleukin 1 receptor-like 1; G-2 and S-phase expressed 1;Nuclear receptor subfamily 2, group E, member 3; Ventral anteriorhomeobox 2; Zinc finger protein 215; DNA segment on chromosome 4(unique) 234 expressed sequence; Carcinoembryonic antigen-related celladhesion molecule 8; Chemokine (C-X-C motif) ligand 10; IL-18;Indoleamine-pyrrole 2,3 dioxygenase; Albumin; Calcium-sensing receptor(hypocalciuric hypercalcemia 1, severe neonatal hyperparathyroidism);Fas ligand (TNF superfamily, member 6); TNFR superfamily, member 17;Calcium channel, voltage-dependent, beta 2 subunit; Parkinson disease(autosomal recessive, juvenile) 2, parkin; Kallikrein 7 (chymotryptic,stratum corneum); Glial cells missing homolog 2; TGF-alpha; Thyrotrophicembryonic factor; AP-2 alpha (activating enhancer binding protein 2alpha); Kallikrein 10; Regulator of G-protein signalling 7; Proteintyrosine phosphatase, receptor-type, Z polypeptide 1; Serine proteaseinhibitor, Kunitz type 1; WNT1 inducible signaling pathway protein 3;Zic family member 3 heterotaxy 1 (odd-paired homolog, Drosophila); TTKprotein kinase; Troponin T1, skeletal, slow; Sciellin; TGFB-inducedfactor 2-like, X-linked; Kallikrein 8 (neuropsin/ovasin); Glucosaminyl(N-acetyl) transferase 2, I-branching enzyme; Ankyrin repeat domain 30A;Relaxin 2; Collagen, type XVII, alpha 1; Gene differentially expressedin prostate; Phosphatase and actin regulator 3; Suppressor of cytokinesignaling 2; Nuclear receptor subfamily 4, group A, member 3;Angiotensin I converting enzyme (peptidyl-dipeptidase A) 1; Hypotheticalprotein MGC17986; Distal-less homeo box 1; LAG1 longevity assurancehomolog 3 (S. cerevisiae); Zygote arrest 1; Interferon, kappa; IL-20;ICEBERG caspase-1 inhibitor; Growth differentiation factor 3; FGF-23;Testis expressed sequence 15; Wingless-type MMTV integration sitefamily, member 8A; SRY (sex determining region Y)-box 7; Carnitinedeficiency-associated, expressed in ventricle 1; Prokineticin 1; CAMPresponsive element binding protein 3-like 3; Caspase recruitment domainfamily, member 15; FLJ23311 protein).

Example 6: Direct Differentiation of Umbilical Cord Lining EpithelialStem Cells (UCEC) into Skin Epidermal Keratinocytes

For differentiation into skin epidermal keratinocytes, umbilical cordepithelial stem cells, UCEC cells, were cultured according to a standardprotocol for the cultivation of keratinocytes. Cell isolation techniqueswere as described above. UCEC were then cultured in serum-freekeratinocyte growth media, KGM®, KGM®-2 (Cambrex Corporation, NewJersey, USA), EpiLife® (Cascade Biologics Inc., Oregon, USA) or inGreen's medium in the presence of irradiated or Mytomycin-C treated 3T3mouse embryonic feeder layer at 37° C., 5% CO₂). UCEC cell morphologythus differentiated resembled human epidermal keratinocytes. Epithelialcells have similar morphology under light microscope and can be easilyturned into fibroblasts using conventional and commercially availablemedia (cf., FIG. 2).

Immunofluorescent analysis shows that the cultivated UCEC also expressepidermal keratinocyte molecular markers such as keratins, desmosome,hemidesmosome and basement membrane components (see also FIG. 10 thatshows that UCEC are qualified to be epithelial cells in general byexpressing a variety of these epithelial cell markers). Accordingly,these results show that umbilical cord epithelial progenitor/stem cellsof the present invention can be differentiated into skin cells such asepidermal keratinocytes which can be used for wound healing and havegreat potential for the development of cultured skin equivalents.

Example 7: Expansion of Umbilical Cord Epithelial and Mesenchymal StemCells Using Repetitive Tissue Explants of Umbilical Cord Lining MembraneTissues

Umbilical cord epithelial and mesenchymal stem cells of the inventionwere expanded using repetitive explants of umbilical cord amnioticmembrane tissue as follows. Briefly, at day 1 of process, tissueexplants were plated onto tissue culture dishes in growth media(DMEM/10% FCS, EpiLife®, KGM®, KGM®-2 or M171) at 37° C., 5% CO₂; mediawas changed every 2 or 3 days. Cell outgrowths started and continuedmigrating from the explants for 7 days. After that, tissue explants weretransferred to other dishes to allow further cell outgrowth. Thisprocess was continued until the explants had diminished in size,preventing further explantation. In this connection it is noted that theexplants progressively shrink in size until they are too small forfurther tissue explant since during the process of cells outgrowing andmigrating from tissue explants, the cells produce proteases to digestand break down tissue. FIG. 16 schematically illustrates the rapid androbust expansion process of umbilical cord epithelial and mesenchymalstem cells achieved using this protocol. Thus, this study demonstratesthe high yield of UCMC and UCEC cells can be obtained from this source,further reflecting the high viability and pro-growth characteristics oftthese cells in comparison with other sources of cells as bone-marrow oradipose-derived stem cells. In addition, being a solid tissue, thesuccessful repetitive explant technique used herein demonstrates thatthe cells of the invention can be uniformly extracted from the entiretissue instead of only certain portions. This allows the maximum numberof cells that can be derived at a low passage instead of passing thecells through many generations causing deterioration of cells.

Example 8: Direct Differentiation of Umbilical Cord Lining MesenchymalCells (UCMC) into Skin Dermal Fibroblasts

For differentiation into skin dermal fibroblasts, umbilical cordmesenchymal stem cells, UCMC cells were cultured according to a standardprotocol for the cultivation of fibroblasts. Cell isolation techniqueswere as described above in Example 6. UCMC were then cultured in DMEM orcommercially available fibroblast growth media (FGM). UCMC cellmorphology thus differentiated resembled human dermal fibroblasts.Mesenchymal cells have similar morphology under light microscope and canbe easily turned into fibroblasts using conventional and commerciallyavailable media (cf., FIG. 3).

Example 9: Direct Differentiation of UCEC into Skin EpidermalKeratinocytes

In an approach similar to Example 6, epithelial stem/progenitor cells ofthe amniotic membrane of the umbilical cord (UCEC) were isolated asdescribed in Example 2. For differentiation of UCEC into epidermalkeratinocytes, the cells were cultured in keratinocyte media (EpiLife®or KGM®) until 100% (cultivation after 5 days shown in FIG. 17-A)confluent before changing the media to DMEM/10% FCS for 3 days to formepidermal cell sheets. As shown in FIG. 17-A (in which photographs oftwo experiments termed “UCEC-10” and UCEC-17 are depicted), aftercultivation in DMEM/10% FCS, UCEC, had differentiated into epidermalkeratinocytes that formed cell sheets (photograph of FIG. 17-A takenafter 10 days). These results thus provide further evidence for thepluripotency of the cells of the present invention.

Example 10: Direct Differentiation of UCMC into Osteoblasts

Mesenchymal cells of the amniotic membrane of the umbilical cord (UCMC)were isolated as described in Example 2. For differentiation of UCMCinto osteoblasts, cells were cultured in DMEM/10% FCS until 100%confluent, and then in starvation medium of serum-free DMEM for another48 hours. UCMC were subjected to osteogenic induction media for 4 weeksbefore subjecting the cells to von Kossa staining (bone cell staining).The osteogenic induction medium contained DMEM/10% FCS; 1% antibiotic(streptomycin and penicillin)/antimycotic (fungizone); 0.01 μM1,25-dihydroxyvitamin D3, 50 μM ascorbate-2-phosphate, 10 mMβ-glycerophosphate, 1% antibiotic (streptomycin andpenicillin)/antimycotic (fungizone).

As shown in FIG. 17B, von Kossa staining of UCMC cells that werecultivated in the osteogenic induction medium indicated bone noduleformation in the UCMC and thus differentiation of the UCMC intoosteoblasts whereas no such differentiation was indicated in untreatedUCMC which were cultured in DMEM/10% FCS without induction underotherwise same conditions as negative control. As a further negativecontrol, dermal fibroblasts from an 8 months old donor and keloidfibroblasts from a 20 year old donor were cultivated under the sameconditions as the induced or un-induced UCMC. Both cell types did notyield a positive result using von Kossa staining, which is a furtherevidence for the pluripotency of UCMC of the present invention and thusto differentiate, for example, also into osteoblasts.

Example 11: Direct Differentiation of UCMC into Adipocytes

Mesenchymal stem/progenitor cells from the amniotic membrane of theumbilical cord (UCMC) were isolated as described in Example 2. Fordifferentiation of UCMC into adipocytes, cells were cultured in DMEM/10%FCS until 100% confluent, and then in starvation medium of serum-freeDMEM for another 48 hours. UCMC were subjected to adipogenic inductionmedia for 4 weeks before subjecting the cells to Oil-Red-O staining. Theadipogenic induction medium contained DMEM/10% FCS; 1% antibiotic(streptomycin and penicillin)/antimycotic (fungizone)); 0.5 mMisobutyl-methylxanthine (IBMX), 1 μM dexamethasone, 10 μM insulin, and200 μM indomethacin.

As shown in FIG. 17C, Oil-Red-O staining of UCMC cells that werecultivated in the adipogenic induction medium indicated fat accumulationin the UCMC and thus differentiation of the UCMC into adipocytes whereasno such differentiation was indicated in untreated UCMC which werecultured in DMEM/10% FCS without induction under otherwise sameconditions as negative control. As a further negative control, dermalfibroblasts from an 8 months old donor and keloid fibroblasts from a 20years old donor were cultivated under the same conditions as the inducedor un-induced UCMC. Both cell types did not yield a positive result inthe staining with Oil-Red-O, which is a further evidence for thepluripotency of UCMC of the present invention and to differentiate, forexample, also into adipocytes.

Example 12: Method to Produce Skin Equivalent Using UCMC and UCECTogether with Collagen as Extracellular Matrix Component

To produce an exemplary skin equivalent of the present invention a6-well tissue-culture tray containing scaffolds made of a 3 μm porouspolycarbonate membrane are used (Transwell®, Corning Incorporated,Massachusetts, USA). Such trays can be obtained from Vitaris AG, Baar,Switzerland. For the collagen ECM layer, sterile rat tail acid-extractedcollagen (1.0-1.7 mg/ml) in 0.05% acetic acid is used. Furthercomponents used for the acellular as well as the cellular ECM medium are10× minimum essential medium with Earle's salts (Gibco-BRL, Maryland,USA), L-glutamine (200 mM, Gibco-BRL, Maryland, USA), Sodium bicarbonate(71.2 mg/ml), DMEM (Gibco-BRL, Maryland, USA), Fetal bovine serum (FBS,Gibco-BRL, Maryland, USA). For the different cell culture medias PTT-4and PTT-7 the following components are used: PTT-4: 90% (v/v) CMRL1066,and 10% (v/v) fetal calve serum.

PTT-7: 99.4% (v/v) EpiLife®, 0.2% (v/v) insulin, 0.2% (v/v) transferrin,0.2% (v/v)selenous acid and 10 ng/ml epithelial growth factor (EGF).

Mesenchymal and epithelial stem cells from the amniotic membrane of theumbilical cord UCMC and UCEC) were isolated and cultivated as describedin Example 2 and 7. UCMC cultured in PTT-4 are shown in FIG. 18b (after7 days of culture) whereas UCEC cultured in PTT-7 are shown in FIG. 18a(after 7 days of culture).

All components described above should be kept on ice. For generating theextracellular matrix containing no cells (acellular ECM), the acellularECM medium components are mixed together in the order listed in Table 1.The colour of the medium solution should be straw-yellow to light pink,and any extreme variation in colour may indicate a pH at which thecollagen may not gel. After mixing together the acellular ECM medium,add 1 ml of this medium to each scaffold, making sure the mixture coatsthe entire bottom of the scaffold. Once the collagen gel has beenpoured, it should not be disturbed in the incubator (37° C., 5% CO₂).

Once the acellular ECM has polymerised (which usually takes about 0.5 toabout 12 hours after the collagen gel has been poured on the scaffold),UCMC that are in culture can be trypsinised and resuspended thoroughlyin PTT-4 cell culture medium to a final concentration of 5×10⁵ cells/ml,ready to mix with collagen solution.

For the cellular ECM medium (see Table 1) all components should be kepton ice. For generating the cell containing extracellular matrix(cellular ECM), the cellular ECM medium components are mixed together inthe order listed in Table 1. The UCMC dissolved in PTT-4 should be addedlast, to ensure that the mix has been neutralised by the addition ofcollagen, so that the cells are not damaged by an alkaline pH. Mix welland add 3 ml to the scaffolds and allow it to gel in the incubator (37°C., 5% CO₂). When the gels are pink and firm (2 to 24 hours later), theyare covered with 3 to 4 ml of PTT-4 and incubated for 4 to 7 days, untilthe gel contraction is stable and complete. The PTT-4 medium allows thecells to differentiate into fibroblasts (FIG. 18b ). Another medium thatis suitable for differentiating UCMC into fibroblasts is the onedescribed in Example 8. During the interval, there is a 50-fold decreasein the volume of the matrix. The culture medium should be changed every2 days.

Trypsinise UCEC when they are ready such that up to 1×10⁶ cells in 50 μIof PTT-7 can be plated in each scaffold. The cell suspension can beplaced in the central, raised, mesa-like portion of the contractedcollagen gel with a 200 μl pipetman.

Do not touch the plates for 2 to 3 hours, while the UCEC adhere in theincubator to the already formed fibroblast layer. After this incubationperiod, PTT-7 can be added into the well (4 ml) on the top of UCEC (2ml) and cultured for up to 7 days. The media should be changed every 2days. The incubation of UCEC with PTT-7 allows the cells todifferentiate into keratinocytes (FIG. 18a ). Another medium that issuitable for differentiating UCEC into keratinocytes is the onedescribed in Example 6.

At this point, the skin equivalent (CSE-1) is grown at the air-liquidinterface using high calcium (0.6 mM) dissolved in PTT-7 culture medium(only 1.5-2 ml) in the well and cultured up to 10 days. The culturemedium should be changed every 2 days.

The skin equivalent (CSE-1) is now ready for histological and electronmicroscopy analysis. It should be noted that CSE-1 growth varies withthe strain of UCEC and UCMC used in the method. As can be seen from thephotographs in FIG. 19 a dermal layer consisting of fibroblasts and anepithelial layer consisting of keratinocytes have been formed. Thephotographs in FIG. 20a show the surface appearance of CSE-1 afterlifting to air-liquid interface. FIG. 20b shows the appearance of UCMCpopulated in collagen lattices of CSE-1.

TABLE 1 Components for the ECM medium Acellular ECM Cellular ECM mediummedium for 6 ml for 18 ml (1 ml / scaffold) (3 ml / scaffold) 10 × DMEM0.59 ml 1.65 ml L-glutamine 0.05 ml 0.15 ml Fetal bovine serum  0.6 ml1.85 ml Sodium 0.17 ml 0.52 ml bicarbonate Collagen  4.6 ml   14 ml UCMC— 5 × 10⁵ cells in 1.5 ml of PTT-4 medium

Example 13: Method to Produce Skin Equivalent Using UCMC and UCEC

In general, the following Example is carried out in the same manner asExample 12. However, in contrast to Example 12 no collagen is used asECM (which in Example 12 is incorporated into the scaffold beforeseeding UCMC into the scaffold). In the present Example, the UCMC cellsthemselves secrete collagen type I and form three-dimensional cellsheets, so making the use of an extra collagen layer superfluous.Production of the collagen by UCMC cells is achieved by adding ascorbicacid to the cell medium PTT-4.

First, the UCMC cells are harvested as described in Example 12. UCEC areseeded on the scaffold in a concentration of 1×10⁵ cells/ml andincubated for 3 days (37° C., 5% CO₂).

After 3 days the culture medium PTT-4 is supplemented with 50 pg/mlascorbic acid. The cells are then incubated for another 2 weeks (37° C.,5% CO₂). Under these conditions, UCMC will self-deposit collagen type Iand form three-dimensional cell sheets, which mimic the extracellularmatrix which was separately generated in Example 12.

For the production of the epidermal layer the same experiments asalready described in Example 12 are carried out.

The skin equivalent (CSE-2) is now ready for histological and electronmicroscopy analysis. It should be noted that CSE-2 growth varies withthe strain of UCEC and UCMC used for the method. The photographs in FIG.21a show the surface appearance of CSE-2 after lifting to air-liquidinterface. FIG. 21b shows the appearance of UCMC populated in collagenlattices of CSE-2.

Example 14: Method to Produce Skin Equivalent Using UCMC, HUVEC and UCECTogether with Collagen as Extracellular Matrix Component

In general, the following example uses the same components and procedureas described in Example 12.

Mesenchymal and epithelial stem cells from the amniotic membrane of theumbilical cord (UCMC and UCEC) were isolated and cultivated as describedin Example 2 and 7. Human Umbilical Vessel Endothelial Cells (HUVEC)were cultured from the umbilical cord vessel using collagenase. Briefly,cord vessels were flushed with PBS to remove all blood. Clamped end ofthe cord: 0.5% collagenase solution was injected into cord vessels andincubated for 20 min at room temperature. Afterwards, the clamps areremoved and the cord vessels are flushed with EGM medium (CambrexCorporation, New Jersey, USA) containing 10% fetal calve serum (FCS) tocollect the HUVE-cell suspension. The cell suspension was centrifugedand the cell pellets collected and subsequently cultured in EGM medium(Cambrex Corporation, New Jersey, USA).

Shortly before the carrying out the experiment, HUVEC cells are culturedin EGM medium (Cambrex Corporation, New Jersey, USA) or M131 medium inan incubator (37° C., 5% CO₂). The cell purity of these cells isconfirmed using immunohistochemical analysis of Factor VIII relatedantigen or von Willebrand factor (data not shown). Briefly, HUVEC wereseeded on cover slips until they reached 80% confluence. Afterwards,they were fixed and incubated with primary antibodies against FactorVIII or antibodies against von Willebrand factor, followed by peroxidaseconjugated secondary antibody. The number of positive cells wasexpressed in percentage of cells marked with Factor VIII or vonWillebrand factor. Positive cells were viewed under microscope to checktheir purity.

All components used for the experiment should be kept on ice. Forgenerating the extracellular matrix containing no cells (acellular ECM),the acellular ECM medium components are mixed together in the orderlisted in Table 2. For further details see the description in experiment12.

Once the acellular ECM has polymerised (which takes place about 0.5 toabout 12 hours after the collagen gel has been poured onto the scaffold)UCMC and HUVEC that are in culture can be trypsinised and resuspendedthoroughly in PTT-4 (for UCMC) and M131 (for HUVEC) cell culture mediumto a final concentration of 5×10⁵ cells/ml (UCMC/HUVEC—1:1 mixture),ready to mix with collagen solution.

For the cellular ECM medium (see Table 2) all components should be kepton ice. For generating the cell containing extracellular matrix(cellular ECM), the cellular ECM medium components are mixed together inthe order listed in Table 2. The UCMC/HUVEC mixture should be addedlast, to ensure that the mix has been neutralised by the addition ofcollagen, so that the cells are not damaged by an alkaline pH. Mix welland add 3 ml to the scaffolds and allow it to gel in the incubator (37°C., 5% CO₂). When the gels are firm (30 min later), they are coveredwith 3 to 4 ml of PTT-4/M131 (1:1) and incubated for 4 to 7 days, untilthe gel contraction is stable and complete. The PTT-4 medium allows thecells to differentiate into fibroblasts. During the interval, there is a50-fold decrease in the volume of the matrix. The culture medium shouldbe changed every 2 days.

UCEC are trypsinised when they are ready such that up to 1×10⁶ cells in50 μl of PTT-7 can be plated in each scaffold. The cell suspension canbe placed in the central, raised, mesa-like portion of the contractedcollagen gel with a 200 μl pipette.

The plates are left untouched for 2 to 3 hours, while the UCEC adhere inthe incubator to the already formed fibroblast layer. After thisincubation period, PTT-7 can be added into the well (4 ml) on the top ofUCEC (2 ml) and cultured for up to 7 days. The media should be changedevery 2 days. The incubation of UCEC with PTT-7 allows the cells todifferentiate into keratinocytes.

At this point, the skin equivalent (CSE-3) is grown at the air-liquidinterface using high calcium (0.6 mM) dissolved in PTT-7 culture medium(only 1.5 to 2 ml) in the well and cultured up to 10 days. The culturemedium should be changed every 2 days.

The skin equivalent (CSE-3) is now ready for histological, confocal,electron microscope and immunological analysis. It should be noted thatCSE-3 growth varies with the strain of UCMC, HUVEC and UCEC used in themethod.

TABLE 2 Components for the ECM medium Acellular ECM Cellular ECM mediumfor 6 ml medium for 18 ml (1 ml / scaffold) (3 ml / scaffold) 10 × DMEM0.59 ml 1.65 ml L-glutamine 0.05 ml 0.15 ml Fetal bovine  0.6 ml 1.85 mlserum Sodium 0.17 ml 0.52 ml bicarbonate Collagen  4.6 ml   14 ml UCMC —5 × 10⁵ cells in 1.5 ml of PTT-4/M131 mixture medium

Example 15: Differentiation of UCEC and UCMC, Respectively, into β-IsletLike Cells

Mesenchymal and epithelial stem cells from the amniotic membrane of theumbilical cord (UCMC and UCEC) were isolated as described in Example 2.

UCMC are incubated in PTT-4 medium (for the composition of PTT-4 (90%(v/v) CMRL1066, 10% (v/v) FCS, supra) or PTT-10 medium. PTT-10 mediumcontains 99.4% (v/v) CMRL-1066 and 0.2% (v/v) insulin, 0.2% (v/v)transferrin and 0.2% (v/v) selenous acid.

UCEC are incubated in PTT-7 medium (for the composition of PTT-7, supra)or PTT-5 and PTT-6 medium. PTT-5 medium contains 98.8% (v/v) CMRL-1066,0.4% (v/v) insulin, 0.4% (v/v) transferrin, 0.4% (v/v) selenous acid and10 ng/ml epidermal growth factor (EGF). PTT-6 medium contains 99.4%(v/v) M171, 0.2% (v/v) insulin, 0.2% (v/v) transferrin, 0.2% (v/v)selenous acid and 10 ng/ml epidermal growth factor (EGF).

The differentiation of UCEC and UCMC, respectively, is induced by adding1 mM nicotinamide to the respective cell culture medium in which thecells are cultivated. The cell culture medium should be changed every 2or 3 days.

The appearance of beta-islet like cells is observed under microscope(FIG. 23; UCEC in PTT-10 with and without the inductor, i.e.nicotinamide). The β-islet like cells are collected for microscopicanalysis. To determine if the cells obtained according to the method ofthe present invention are indeed β-islet like cells one of the methodsthat is described in the Technical Manual of StemCell Technologies Inc.,Title: In-vitro differentiation of murine ES cells into pancreaticislet-like clusters, or “Epithelial-to-mesenchymal transition generatesproliferative human islet precursor cells”, Science, 2004, 306, p.2261-2264 was used.

In the following it is described an alternative method for the inductionof insulin-producing cell differentiation of UCEC (CLEC). UCEC have beenincubated with one of the media as described above (PTT-5, PTT-6 orPTT-7 medium). For the induction of differentiation of UCEC intoinsulin-producing cells these cells have been exposed to ESCult medium(purchased from StemCell Technologies Inc., Vancouver, Canada) or BBRC06medium for 7 days.

ESCult medium (StemCell Technologies Inc., Vancouver, Canada) contains100 microgram/ml nicotinamide added in together with 20 ml/l B27 and 10ml/l N2 supplements.

BBRC06 medium contains serum-free DMEM/F12 medium with 17.5 mM, glucosein the presence of nicotinamide 10 mM, activin-A 2 nM, exendin-4, 10 nM,hepatocyte growth factor 100 μM, and pentagastrin 10 nM (Sigma-Aldrich,Missouri, USA) as well as B-27 serum-free supplement, N-2 Supplement(StemCell Technologies Inc., Vancouver, Canada), and 1%penicillin/streptomycin 5000 U/L (Biochem. Biophys. Res. Commun. 2006,March 24; 341(4) p. 1135-40).

After the incubation for 7 days in ES Cult medium or BBRC06 medium, thetotal RNA were harvested using RNeasy® extraction kits from QIAGEN®(Hilden, Germany) for RNA extraction and purification and single sampleswere subjected to RT-PCT assays to detect insulin gene expression. Aninsulin primer was used as a positive control as described in Timper K.,Seboek D. et al., Biochem Biophys Res Commun., 2006 Mar. 24, 341(4), p.1135-40.

FIG. 25 shows the results of this alternative induction method. FIG. 25shows insulin expression in multiple samples of UCEC under induction ofES Cult medium or BBRC06 medium. Samples designated with CLEC25, 28 and30 indicate different samples derived from different donors of umbilicalcords. Samples designated with CLEC30(1) and CLEC30 (2) indicateduplicates of the same sample. Thus, it is proved that UCEC have thepotential to differentiate into insulin-producing cells which can beused for the treatment of diabetes.

Example 16: Differentiation of UCEC into Mucin-Producing Cells

Epithelial stem cells from the amniotic membrane of the umbilical cord(UCEC) were isolated as described in Example 2.

The isolated UCEC are grown in the cell culture medium PTT-5 or PTT-6(37° C., 5% CO₂) which composition has already been described in Example15. It was the surprising finding of the present invention that UCECproduce mucin using PTT-5 and PTT-6 to culture UCEC (see FIG. 22a ).During the course of pipetting and changing media viscosity of the cellculture supernatants was observed.

Mucin clot test: The mucin clot test is an assessment of the quality andquantity of mucin produced by UCEC cultured in PTT-5 or PTT-6. This testis also described in general by Corfield A. P., Glycoprotein method andprocotols: The Mucins, page 29-65. Humana Press 2000; Gatter R. A. andSchumacher R. H., A practical handbook of join fluid analysis, page59-63, Lea & Febiger, 1991. Within this test, UCEC cell cultureconditioned media is expelled into 7N glacial acetic acid. The aceticacid causes the mucin to form a clot. UCEC cell culture conditionedmedia containing normal mucin appeared as clear fluid with a tight, ropyclot.

To quantify the amount of mucin produced by UCEC a SDS-PAGE andsubsequently a Coomassie staining are carried out (see FIG. 22b ). Forthe SDS-PAGE, 2.5 ml of cell culture media collected from UCEC cellculture were concentrated using 100 kDa cut-off membrane Centrisart® I(Sartorius AG, Germany). 100 μl concentrated supernatants were loadedinto 6% SDS-PAGE for electrophoresis. Gels were then stained withCoomassie and photographs were taken.

Example 17: Direct Differentiation of UCMC into Chondrocytes(Chondrogenic Lineage)

Similar to the development of UCMC in osteoblasts (see Example 10) theyalso have the ability to develop into chondrocytes which make up thecartilage.

For the development of cartilage, mesenchymal cells of the amnioticmembrane of the umbilical cord (UCMC) were isolated as described inExample 2. For differentiation of UCMC into chondrocytes, cells werecultured in DMEM/10% FCS until 100% confluent. They were then exposed toPTT-5 medium supplemented with 10 ng/mL transforming growth factor-β3(TGF-β3; R&D Systems, Minneapolis, USA), 100 nM dexamethasone, 50 mg/mLascorbic acid, 100 mg/mL sodium pyruvate, 40 mg/mL proline(Sigma-Aldrich, Missouri, USA), for 4 weeks. Cell layers were stainedwith Alcian Blue (it stains acid mucopolysaccharides andglycosaminoglycans).

Positive staining of chondrocytes or a chondrogenic lineage with AlcianBlue was observed in FIG. 24B in comparison with the control in which nosuch differentiation was indicated (FIG. 24A). The control consisted ofuntreated UCMC which were cultured in DMEM/1% FCS without induction withsupplemented PTT-5 (supra) under otherwise same conditions. The resultsshow that UCMC have the potential to form the chondrocytes of thecartilage for cartilage repair and regeneration. Cells can be applied tothe body by use of a scaffold, e.g. TissueFleece® (Baxter AG, Austria;described in Example 21) or a hydrogel.

Example 18: Differentiation of UCMC into Dopamine-Producing Cells

This example describes the differentiation of UCMC into dopamine andtyrosine hydroxylase (TH)-producing cells.

For the development of dopamine and TH, mesenchymal cells of theamniotic membrane of the umbilical cord (UCMC) were isolated asdescribed in Example 2.

UCMC were cultured in 100 mm tissue culture dishes at a density of200000 cells and maintained in PTT-4 medium for 5 days until 80%confluent. The cells were then exposed to PTT-2 medium for another 48hours. After incubation the cell culture supernatants were collected foranalysis. PTT-2 medium is a mixture of M154 a melanocyte culture mediumand EpiLife® (Cascade Biologics Inc., Oregon, USA) at ratio of 3:1.

UCMC cells or conditioned media (supernatant, supra) were subjected toWestern blot or immunohistochemistry (IHC) analysis. FIG. 26A shows THsecretion of CLMC (UCMC) cells into conditioned media. More TH secretionwas observed in lane 4 and 5 when exposed to PTT-2 medium. FIG. 26Bshows the expression of Dopamine by CLMC (UCMC) cells. FIG. 26C showsnegative control. These UCMC cells are coaxed with dopamine. They areremained undifferentiated, but a high amount of dopamine can bedetected. Indication: UCMC have potential to produce Dopamine andDopamine precursor-TH.

Example 19: Differentiation of UCMC and UCEC into HLA-G-Producing Cells

This example describes the differentiation of UCMC and UCEC intoHLA-G-producing cells. HLA-G is a HLA class I antigen which is mainlyexpressed in the placenta where it presumably protects the fetus againstattacks of the immune system of its mother. HLA-G is a special HLA andhas been implicated in various immune-mediated diseases and conditions,like organ-, cell transplantation and auto-immune diseases. Examples forsuch autoimmune diseases are multiple sclerosis, rheumatoid arthritis,type I diabetes mellitus, psoriasis, thyroid diseases, systemic lupuserythematosus, scleroderma or celiac disease. Specific variants havebeen reported as associated with risks of miscarriage, and preeclampsia.HLA typing is critical for matching donor and recipients for bone marrowtransplantation; the use of well-matched donors increases survival anddecreases graft vs. host disease. HLA typing is also important for solidorgan transplantation, as well as other areas of use.

For the development of HLA-G, epithelial and mesenchymal cells of theamniotic membrane of the umbilical cord (UCEC and UCMC, respectively)were isolated as described in Example 2.

Total RNA and conditioned media were collected from UCMC and UCEC cellsand subjected to RT-PCR and Western blot analysis. FIG. 27A showsexpression of HLA-G mRNA in both UCMC and UCEC. JAR trophoblast cellsserved as positive control for HLA-G expression. FIG. 27B showssecretion of the HLA-G protein by UCEC cells in conditioned media.

This experiment shows for the first time that naïve UCEC express andproduce HLA-G. A specific induction of UCEC for the production of HLA-Gis not necessary. The HLA-G producing UCEC and UCMC cells have goodimmunosuppressive properties. These cells are low immunogenenic and goodcandidates for allogenic transplantation.

Example 20: Induction of Proliferation of Aged Skin Keratinocytes (asK)Using UCMC

In the following example it is demonstrated how UCMC can induce cellproliferation of aged skin keratinocytes (asK) and human dermalfibroblasts (NF).

Mesenchymal cells of the amniotic membrane of the umbilical cord (UCMC)were isolated as described in Example 2. UCMC were cultured in PTT-4medium until 80% confluent. Afterwards, the cells were harvested andcentrifuged at 1200 rpm for about 10 min. After centrifugation,hypotonic water was added to the cell pellets with a ratio of 1 mlhypotonic water for 8 million cells. Total cell lysates were centrifugedat 4000 rpm for 30 min at 4° C. The clear phase of “UCMC extracts” werecollected and stored in −30° C. Aged skin keratinocytes (asK) wereisolated from chronological aged skin (patient who was more than 60years old). asK cells were seeded in 24 well plates at a density of 4000cells/well and maintained in growth EpiLife® medium (Cascade BiologicsInc., Oregon, USA) for 24 h. asK cells were then exposed to basalEpiLife® medium (Cascade Biologics Inc., Oregon, USA) for 48 h beforeadding in the UCMC extract at different dilutions of 2.5%, 5%, 10%, and20% diluted in basal EpiLife® medium. Standard MTT assays were performedat different time intervals. FIG. 28A shows that an UCMC extract inducedasK cells proliferation at concentrations at 2.5%, 5% and 10% at day 6and 7. The “control” sample bar displayed in FIG. 28A represents agedskin keratinocytes maintained in basal EpiLife® medium without additionof UCMC extract or growth factors. The term “ask 10(1) p3” refers toaged-skin keratinocytes which have been passaged three times. The“positive” sample bar displayed in FIG. 28A represents cells which weremaintained in optimal condition of growth media (basal mediumEpiLife®+growth factors) without UCMC extract. Similarly, different celllines of human dermal fibroblasts (NF125 and NF119, respectively) weretreated with “UCMC extract” as described above. The results of theseexperiments are shown in FIGS. 28B and 28C.

As “UCMC extract” has positive effects on skin keratinocytes andfibroblasts, the extract can be prepared for promoting wound healing,skin repair, regeneration and rejuvenation.

Example 21: Use of Different Scaffold Materials for Cultivation of UCMC

In a first experiment, mesenchymal tissue equivalents (MTE) wereprepared by UCMC cell-populated in collagen lattices. To prepareorganotypic coculture constructs, MTE were transferred onto Transwellinserts (Corning Inc.). CLEC or human skin keratinocytes were seededonto MTE at density of 100,000 cells/cm² and maintained in EpiLifemedium. The organotypic coculture constructs were then raised toair-liquid interface for 3 weeks. The constructs were then subjected toH&E staining for histological analysis (see FIGS. 29 A and 29B).

A second experiment carried out demonstrates the ability of UCMC to beinoculation in commercially available biomaterial scaffolds such asTissuFleece® (Baxter AG, Austria), INTEGRA Bilayer Matrix WoundDressing™ (Neuro Sciences, New Jersey, USA), BoneSave® (Stryker Inc.,MI, USA) or Synthese (AO).

The active ingredient of TissueFleece® E (Baxter AG, Austria) is ascaffold that consists of free-dried horse skin collagen. 1 cm² ofTissueFleece® contains 2.8 mg of native collagen fibrils. Generally, thecontact of collagen with blood results in the aggregation ofthrombocytes which then adhere in great numbers to the collagen matrix,disintegrate, and release coagulation factors which, in combination withplasma factors, lead to the formation of fibrin. The collagen matrixadditionally enhances the coagulum. Owing to its structure, TissuFleece®collagen fleece is capable of absorbing large quantities of liquid. Byway of this merely mechanical process, the UCMC are absorbed.Consequently, the formation of granulation tissue is accelerated.

INTEGRA Bilayer Matrix Wound Dressing™ (in the following only referredto as Integra®) is a scaffold that is comprised of a porous matrix ofcross-linked bovine tendon collagen and glycosaminoglycan and asemi-permeable polysiloxane (silicone) layer. The semi-permeablesilicone membrane controls water vapor loss, provides a flexibleadherent covering for the wound surface and adds increased tear strengthto the device. The collagen-glycosaminoglycan biodegradable matrixprovides a scaffold for cellular invasion and capillary growth.

BoneSave® (Stryker Inc., MI, USA) is a scaffold that consists of calciumphosphate ceramic.

ChronOS® (Synthes GmbH, Switzerland) is a scaffold that consists ofbeta-tricalcium phosphate.

For the experiment mesenchymal cells of the amniotic membrane of theumbilical cord (UCMC) were isolated as described in Example 2. UCMC werecultured in PTT-4 medium until 80% confluent. Cells were harvested andcentrifuged at 1200 rpm for about 5 min to obtain cell pellets. Toinoculate UCMC in TissuFleece®, Integra®, BoneSave® (Stryker Inc., MI,USA) and ChronOS® (Synthes GmbH, Switzerland), cell pellets weresuspended in PTT-4 medium at a ratio of 8 million cells per 1 ml medium.UCMC cell suspension was then seeded on TissuFleece® or Integra® sheetsat a density of 100000 cells/cm². Bone graft granules of BoneSave®(Stryker Inc., MI, USA) or ChronOS® (Synthes GmbH, Switzerland) weresubmerged and mixed well in UCMC cell suspension. UCMC cell inoculatedbiomaterials were maintained in PTT-4 medium for 48 hours in cellculture incubator at 37° C. and subjected to confocal microscopyanalysis after staining with FDA and propidium iodide. Living UCMC cellswere inoculated in TissuFleece® (FIG. 30A) and BoneSave® (Stryker Inc.,MI, USA) (FIG. 30B), incubated as described above, afterwards stainedwith FDA and propidium iodide (PI), and then subjected to confocalmicroscopy analysis. The results are shown in FIGS. 30A and 30B. Cellsstained with PI appear red (indicated by “R” in FIGS. 30A and 30B) andcells stained with FDA appear green (indicated by “G” in FIGS. 30A and30B).

Both Fluorescein diacetate (FDA) (50 μg/ml) and PI (25 μg/ml) wereprepared using 1×PBS. For staining of the cells, they were taken outfrom incubator and washed twice with 1×PBS. Afterwards they have beenincubated with FDA (50 μg/ml)] in a 37° C. incubator for 15 minutes.After this, the cells were rinsed 2 times with 1×PBS. This was followedby counter staining with PI (25 μg/ml) at room temperature for 5minutes. Then, the cells were washed 2 times with 1×PBS and the sampleswere kept in 1×PBS to prevent drying. After this, the cells wereobserved under confocal microscope as described above.

The results of this experiment show that UCMC are growing on differentkind of scaffolds. Thus, UCMC can be used to engineer living soft andhard tissue for repair and regeneration.

Example 22: Implantation of UCMC-Populated Collagen Scaffolds intoImmuno-Competent Mice

This experiment demonstrates the angiogenic property of UCMC. The cellswere seeded into the scaffolds as previously described in Example 12.FIG. 31A shows appearance of UCMC-populated collagen lattices (scaffold)in vitro. FIG. 31B shows implanted control cell-free collagen latticesand UCMC-populated collagen lattices in mice at day 21. No sign ofimmuno-rejection was observed. Macroscopic vascularization was observedin implanted UCMC-populated collagen lattice at day 21. FIG. 31C showsmicroscopic vascularization (indicated by arrows) of UCMC-populatedcollagen lattices.

This experiment clearly demonstrates the angiogenic property of UCMC.These cells can thus be used to enhance angiogenesis in tissue repairand regeneration, and to treat ischemic disorders.

Example 23: Clinical Application of UCMC for the Treatment of FullThickness Burns Wounds

This experiment shows the treatment of a 53 year old female patient whosuffered from full thickness burns. In general, these kind of woundsrequire a skin graft to heal completely.

For the experiment mesenchymal cells of the amniotic membrane of theumbilical cord (UCMC) were isolated as described in Example 2.

For this experiment the patient to be treated was first put undergeneral anesthesia and then the burn necrotic tissue was surgicallyexcised using surgical currets before applying the UCMC populatedBiobrane®-L nylon membrane (Dow Hickam Pharmaceuticals, Texas, USA) tothe wound of the patient (see FIG. 32B).

In the present experiment the Biobrane®-L nylon membrane was cut intoround pieces to fit into 32 mm tissue culture dishes. UCMC were culturedin 150 mm tissue culture dishes and harvested by cell scraping,centrifuged and counted as previously described herein. Membrane pieces(see FIG. 32B, first picture) were wetted with DMEM medium for 48 hoursbefore seeding UCMC with a density of 100000 cells/cm² on the membrane.

FIG. 32A shows wound bed preparation on full thickness burns (3^(rd)degree) of 53 years old female patient. UCMC were inoculated ontoBiobrane®-L wound dressings (Dow Hickam Pharmaceuticals, Texas, USA).UCMC-Biobrane constructs were transferred onto wounds (FIG. 32B).Complete healing was seen (FIG. 32C) at day 7 without skin graft andstable up to 3 month follow-up. This case shows that UCMC may havehealing power of stem cells to heal this kind of burn wounds withoutusing a skin graft, indicating that this technology may replaceautologous skin graft in the future.

In FIG. 34 the treatment of full-thickness burns wound of 2 years oldmale patient is shown. The experiment was conducted similar to the onedescribed above. UCMC were cultured on tissue culture dishes in DMEM/10%FCS until confluent. Cells were then harvested by scraping and mixedwith SoloSite® gel (Smith & Nephew, Hull, UK) and pasted onto wound atdensity of 1 million cells/cm². SoloSite® is a hydrogel wound dressingwith preservatives which comprises a water swellable polymer thatremains gel-like until saturated. It can donate moisture to rehydratenon-viable tissue. It absorbs exudate while retaining its structure inthe wound. Complete healing with this method was observed at day 5without skin graft.

Example 24: Clinical Application of UCMC for the Treatment ofPartial-Thickness Wounds

This experiment demonstrates the clinical application of UCMC for thetreatment of partial-thickness wounds (2^(nd) degree) of a 2 year old,male patient. The experiment (wound preparation and preparation of thewound dressing etc.) was carried out as described in Example 23. UCMCwere cultured on Tegaderm® wound dressing (3M Health Care, Minnesota,USA) and transferred onto wound.

The Tegaderm® wound dressing is a fast wicking, non-swellingpolyurethane foam with a highly breathable film backing which preventswound exudate strike-through and is a barrier to outside contaminationwhile the dressing remains intact without leakage. The wound dressingconsists of a urethane film backing (5-10 wt.-%), polyurethane foam(90-95 wt.-%) and a small amount of ink (0.1-1 wt.-%).

A complete healing of the partial-thickness wound was observed at day 3(see FIG. 33). The left arrow in FIG. 33 indicates area A, i.e. the partof the wound that was treated with UCMC-loaded Tegaderm® wound dressing.The right arrow indicates area B, i.e. the part of the wound that wastreated by use of the conventional method.

Example 25: Clinical Application of UCMC for the Treatment of aNon-Healing Radiation Wound

This example demonstrates the clinical application of UCMC for thetreatment of a non-healing radiation wound in a 1 year old child, whohad hemangioma. The original wound did not heal over a period of 90 dayswith conventional wound treatment. The experiment was carried out asdescribed in Example 23. UCMC were cultured onto Tegaderm® wounddressing at density of 100000 cells/cm² and transferred onto woundstwice a week. The radiation wound was healed completely over a period of20 days of UCMC cell therapy as can be seen in FIG. 35.

Example 26: Clinical Application of UCMC for Treatment of Non-HealingDiabetic Wound and Non-Healing Diabetic Food Wound

These experiments demonstrate the clinical application of UCMC fortreatment of a non-healing diabetic wound (FIG. 36), a non-healingdiabetic food wound (FIG. 37B) and a failed skin flap donor site wound(FIG. 37A). The latter two were failed to heal under conventionaltreatment over a period of 6 years.

UCMC were cultured and mixed with SoloSite® gel (Smith & Nephew, Hull,UK) as described in example 23. The UCMC/SoloSite® gel mixture waspasted onto the wounds at a density of 1 million cells/cm². Theapplication to the wounds was performed once a week. Complete healing ofthe non-healing diabetic wound was observed at day 26 (FIG. 36) whereasin case of the non-healing diabetic food wound (FIG. 37B) and the failedskin flap donor site wound (FIG. 37A) a progress of wound healing couldbe observed.

Example 27: Direct Differentiation of UCEC into Hepatocytes

Epithelial stem/progenitor cells from the amniotic membrane of theumbilical cord (UCEC) were isolated as described in Example 2. Fordifferentiation of UCEC into hepatocytes, the cells were exposed toBBRC06H medium containing Oncostatin-M (50 μg/ml) (BBRC06H medium ismodified version of BBRC06 as described in example 15 without additionof nicotinamide and with addition of Oncostatin-M at 50 μg/ml).

FIG. 38 shows albumin expression of UCEC after induction with BBRC06Hmedium containing Oncostatin-M (50 μg/ml). Alpha Feto Protein is a stemcell marker of hepato stem/progenitor cells. When induced by inductionmedium, UCEC differentiate into mature hepatocytes producing morealbumin. Tubulin is a house-keeping gene to show equal loading inwestern blot assay. This experiment shows that UCEC have the potentialto differentiate into hepatocytes, which can be used for the treatmentof liver diseases or in-vitro models for testing cytotoxicity of newdrugs.

What is claimed is:
 1. A method of promoting skin rejuvenation in asubject comprising: administering to the subject an effective amount ofa cellular extract of epithelial or mesenchymal stem/progenitor cellsisolated from the amniotic membrane of the umbilical cord, wherein thecellular extract contains growth factors and peptides and is in the formof a supernatant into which the epithelial or mesenchymalstem/progenitor cells secrete the growth factors and peptides.